Curable adhesive composition

ABSTRACT

An adhesive curable composition which comprises, as the main component, a vinyl polymer having at least one crosslinkable silyl group represented by the general formula (1). Said composition can be used as a sealing composition, a pressure sensitive adhesive composition and a coating composition. 
     
       
         —[Si(R 1 ) 2-b (Y) b O] m—Si(R   2 ) 3-a (Y) a   (1)  
       
     
     wherein R 1 and R   2  are the same or different and each represents an alkyl group containing 1 to 20 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or a triorganosiloxy group represented by the formula (R′) 3 SiO— (in which R′ represents a monovalent hydrocarbon group containing 1 to 20 carbon atoms and the plural R′ groups may be the same or different) and, when there are two or more R 1  or R 2  groups, they may be the same or different; Y represents a hydroxyl group or a hydrolyzable group and, when there are two or more Y groups, they may be the same or different; a represents 0, 1, 2 or 3; b represents 0, 1 or 2; and m represents an integer of 0 to 19; with the condition that a, b and m satisfy the relation a+mb≧1.

TECHNICAL FIELD

The present invention relates to a curable composition which hasadhesiveness or stickiness, namely an adhesive curable composition. Moreparticularly, it relates to a sealing composition which shows goodweathering resistance and heat resistance, has good handling propertiesowing to its low viscosity, can be packed in one container and showsgood coating properties, and to a coating composition or pressuresensitive adhesive composition which has good weathering resistance andheat resistance in which the solvent content can be markedly reduced (toattain a high solid content) owing to the intrinsic low viscosity ofsaid composition and which is therefore less unfriendly to theenvironment.

BACKGROUND ART

In the field of building and construction, among others, silicone typesealing materials having a silicon-containing group which has a hydroxylor hydrolyzable group bound to a silicon atom and can be crosslinkedunder formation of siloxane bonds (hereinafter referred to also as“crosslinkable silyl group”) have so far generally been widely used assealing compositions excellent in weathering resistance and heatresistance. It is pointed out, however, that silicone-based sealingmaterials have drawbacks such as poor adhesion of paints and tendencytoward staining areas around joints, although they are excellent notonly in weathering resistance but also in resistance to movement andcold workability, among others.

Recently, crosslinkable silyl-terminated polyisobutylene-based sealingmaterials have been proposed as new-type weathering-resistant sealingmaterials. It is pointed out, however, that polyisobutylene-basedsealing materials are high in viscosity, hence poor in workability, andhardly permeable to moisture and therefore difficult to subject toone-component packaging, although they are excellent in weatheringresistance and resistance to permeation of moisture.

Vinyl or (meth)acrylic polymers are excellent in weathering resistanceand therefore have the possibility of their being useful as basepolymers in high weathering resistance sealing materials. In particular,crosslinkable silyl-containing (meth)acrylic polymers are verypromising, since they have already been put to practical use in highweathering resistance paint compositions. However, said polymers aregenerally produced by copolymerizing a crosslinkable silyl-containing(meth)acrylic monomer and another vinyl monomer, so that crosslinkablesilyl groups are randomly introduced into molecular chains. Therefore,difficulties arise in using said polymers in those elastic sealingmaterials which are required to have low modulus and high elongationcharacteristics. A vinyl or (meth)acrylic polymer, if it has acrosslinkable silyl group terminally to the main chain, would beexpected to be utilizable as a new-type weathering-resistant sealingmaterial.

On the other hand, acrylic pressure sensitive adhesives as well asnatural rubber-based pressure sensitive adhesives are produced in largequantities, since they have well-balanced adhesive characteristicswithout the aid of any tackifier resin. Since, however, acrylic pressuresensitive adhesives are disadvantageously poor in cohesion owing totheir molecular weight and molecular weight distribution, it is usual tosubject them to crosslinking for cohesion improvement. For suchcrosslinking, various techniques have been developed. For example,methods have been proposed which comprise adding a crosslinking agentsuch as a polyisocyanate compound, epoxy compound, polybasic carboxylicacid, polyamine compound, phenolic resin, or sulfur compound, forinstance; or carrying out crosslinking of crosslinkable silyl-containingacrylic polymers in the presence of a condensation catalyst. Inparticular, pressure sensitive adhesives comprising a crosslinkablesilyl-containing acrylic polymer as the main component are advantageousin that they are cured by crosslinking via siloxane bonding andtherefore are excellent in weathering resistance.

However, even those pressure sensitive adhesives in which acrosslinkable silyl-containing (meth)acrylic polymer is used havecrosslinkable silyl groups randomly introduced therein, so that, when alow-molecular polymer is used to attain a reduced viscosity, thedistance between crosslinking sites becomes short. In that case, theproblem is that elastic properties required of pressure sensitiveadhesives cannot be obtained. For providing pressure sensitive adhesiveswith elastic properties, a method is available which comprises using ahigh-molecular polymer as the above polymer and reducing the amount ofthe crosslinkable silyl-containing monomer to thereby increase thedistance between crosslinking sites. However, the use of ahigh-molecular polymer as the above polymer leads to a high viscosity orsolid state and, therefore, for using the resulting polymer as apressure sensitive adhesive, it is necessary to use a solvent in fairlylarge amounts to reduce the viscosity. In the case of such a solventtype pressure sensitive adhesive, the solvent is evaporated afterapplication of the pressure sensitive adhesive to a film or likesubstrate. For this, a lot of heat energy is required and, in addition,the solvent may cause a fire or adversely affect the human body. It istherefore required that no solvent be used or a high solid content beattained. The use of a high-molecular polymer as the above polymer thushas its limits.

To solve the above problem, it has been proposed that a (meth)acryliccopolymer which meets the relatively low molecular weight and lowviscosity requirements and has a crosslinkable silyl group introducedtherein terminally to the main chain be used as the base polymer inpressure sensitive adhesive compositions.

Crosslinking silyl-containing vinyl or (meth)acrylic polymers are alsoused as base polymers in high weathering resistance solvent or waterpaint compositions since, when cured by crosslinking in the presence ofan appropriate condensation catalyst, they give coat films excellent inweathering resistance.

As a result of the recent increasing interest in the earth environment,the use of solvent paints which evaporate a large amounts of solvents israther refrained but it is demanded that paint compositions have a stillhigher solid content. For achieving a high solid content in vinyl or(meth)acrylic paints while securing the spreadability in the coatingstep, it is generally necessary to reduce the viscosity and, therefore,to reduce the molecular weight of the polymer. However, when themolecular weight is reduced, a problem arises, namely the weatheringresistance intrinsic in vinyl or (meth)acrylic polymers is lost.

As a method of solving this problem, a method is presumable whichcomprises reducing the molecular weight distribution, namely the ratio(Mw/Mn) of weight average molecular weight (Mw) to number averagemolecular weight (Mn), of a vinyl or (meth)acrylic polymer, asdetermined by gel permeation chromatography, to thereby reduce thepolymer viscosity and thus attain a high solid content. However, thosevinyl or (meth)acrylic polymers which are used in paint compositions aregenerally produced by free radical polymerization, so that only thosepolymers which have a wide molecular weight distribution (generallyhaving an Mw/Mn value of not less than 2) can be obtained.

Further, the reduction in molecular weight for attaining a low viscosityresults in a shortened distance between sites of crosslinking, which inreturn leads to formation, in the step of curing, of coat films with avery high crosslinking density. As a result, the coat films obtained arevery poor in elastic properties and the problem that said films may notfollow the deformation of substrates will arise. One means to solve thisproblem is to use a vinyl or (meth)acrylic polymer having acrosslinkable silyl group terminally to the main chain as the maincomponent. The crosslinkable silyl-terminated main chain makes itpossible to increase the distance between crosslinking sites whilemaintaining an adequate molecular weight and, as a result, to providethe resulting coat films with elastic properties.

As mentioned hereinabove, it is necessary, for obtaining low-viscositysealing compositions, pressure sensitive adhesive compositions and paintcompositions without decreasing physical properties, to obtain a vinylor (meth)acrylic polymer having a crosslinkable silyl-terminated mainchain and a narrow molecular weight distribution. It is not easy toproduce such a polymer by the prior art technology.

As an attempt to synthesize such a polymer having a crosslinkablesilyl-terminated main chain, a method is disclosed in Japanese KokokuPublication Hei-3-14068, for example, which comprises polymerizing a(meth)acrylic monomer in the presence of a crosslinkablesilyl-containing mercaptan, a crosslinkable silyl-containing disulfideand a crosslinkable silyl-containing radical polymerization initiator.Further, in Japanese Kokoku Publication Hei-04-55444, a method isdisclosed which comprises polymerizing an acrylic monomer in thepresence of a crosslinkable silyl-containing hydrosilane compound or atetrahalosilane. It is difficult by these methods, however, to introducethe crosslinkable silyl group into the polymer at both termini withsureness. Thus, an insufficient gel fraction, hence insufficientcurability, will result.

Further, Japanese Kokai Publication Hei-6-211922 discloses a roomtemperature-curable composition which comprises a crosslinkablesilyl-terminated (meth)acrylic polymer obtained by synthesizing ahydroxyl-terminated acrylic polymer by using a hydroxyl-containingpolysulfide in excess relative to an initiator, followed by conversionof the hydroxyl group. This synthetic method makes it possible to obtaina (meth)acrylic polymer with a relatively high percentage of terminalcrosslinkable silyl groups but requires the use of a large amount of anexpensive hydroxyl-containing polysulfide, which is a chain transferagent. This is a problem from the production process viewpoint. Anotherproblem is that the viscosity of the polymer becomes high since themolecular weight distribution becomes wide.

Accordingly, in view of the foregoing, the present invention has for itsobject to produce an adhesive curable composition excellent inweathering resistance and heat resistance and having a low viscosity byusing, as the main component, a vinyl polymer having at least onecrosslinkable silyl group.

SUMMARY OF THE INVENTION

The invention thus provides an adhesive curable composition whichcomprises, as the main component, a vinyl polymer having at least onecrosslinkable silyl group represented by the following general formula(1):

—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (1)

wherein R¹ and R² are the same or different and each represents an alkylgroup containing 1 to 20 carbon atoms, an aryl group containing 6 to 20carbon atoms, an aralkyl group containing 7 to 20 carbon atoms or atriorganosiloxy group represented by the formula (R′)₃SiO— (in which R′represents a monovalent hydrocarbon group containing 1 to 20 carbonatoms and the plural R′ groups may be the same or different) and, whenthere are two or more R¹ or R² groups, they may be the same ordifferent; Y represents a hydroxyl group or a hydrolyzable group and,when there are two or more Y groups, they may be the same or different;a represents 0, 1, 2 or 3; b represents 0, 1 or 2; and m represents aninteger of 0 to 19; with the condition that a, b and m satisfy therelation a+mb≧1.

DETAILED DESCRIPTION OF THE INVENTION

The adhesive curable resin composition of the present inventioncomprises a vinyl polymer having at least one crosslinkable silyl grouprepresented by the above general formula (1).

In the above general formula (1), R¹ and R² are the same or differentand each represents an alkyl group containing 1 to 20 carbon atoms, anaryl group containing 6 to 20 carbon atoms, an aralkyl group containing7 to 20 carbon atoms or a triorganosiloxy group represented by theformula (R′)₃SiO— (in which R′ represents a monovalent hydrocarbon groupcontaining 1 to 20 carbon atoms and the plural R′ groups may be the sameor different). When there are two or more R¹ or R² groups, they may bethe same or different.

In the above general formula (1), Y represents a hydroxyl group or ahydrolyzable group. When there are two or more Y groups, they may be thesame or different.

Said hydrolyzable group is not particularly restricted but includes,among others, a hydrogen atom, a halogen atom and alkoxyl, acyloxyl,ketoximato, amino, amido, aminoxyl, mercapto, alkenyloxyl and likegroups. Among them, alkoxyl groups are preferred because of mildhydrolyzability and ease of handling.

In the above general formula (1), a represents 0, 1, 2 or 3, and brepresents 0, 1 or 2. m represents an integer of 0 to 19. The totalnumber of hydroxyl and hydrolyzable groups, namely a+mb, is an integernot less than 1. Thus, at least one Y is contained in the above generalformula (1).

The number of silicon atoms constituting the above crosslinkable silylgroup may be 1 or 2 or more. When the silicon atoms are joined togethervia siloxane bonding, said number may be up to about 20.

Vinyl monomers constituting the main chain of the above vinyl monomerhaving at least one crosslinkable silyl group are not particularlyrestricted. As an example, there can be mentioned, any of (meth)acrylicacid type monomers such as (meth)acrylic acid, methyl (meth)acrylate,ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate,n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl(meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate,cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl(meth) acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl(meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate,3-methoxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl(meth)acrylate, 2-aminoethyl (meth)acrylate,γ-(methacryloyloxypropyl)trimethoxysilane, (meth)acrylic acid-ethyleneoxide adduct, trifluoromethylmethyl (meth)acrylate,2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl(meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate,2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate,diperfluoromethylmethyl (meth)acrylate,2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate,2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl(meth)acrylate, 2-perfluorohexadecylethyl (meth)acrylate, etc.; styrenetype monomers such as styrene, vinyltoluene, α-methylstyrene,chlorostyrene, styrenesulfonic acid and salts thereof, etc.;fluorine-containing vinyl monomers such as perfluoroethylene,perfluoropropylene, vinylidene fluoride, etc.; silicon-containing vinylmonomers such as vinyltrimethoxysilane, vinyltriethoxysilane, etc.;maleic anhydride, maleic acid, maleic acid monoalkyl esters and dialkylesters; fumaric acid, fumaric acid monoalkyl esters and dialkyl esters;maleimide monomers such as maleimide, methylmaleimide, ethylmaleimide,propylmaleimide, butylmaleimide, hexylmaleimide, octyl-maleimide,dodecylmaleimide, stearylmaleimide, phenyl-maleimide,cyclohexylmaleimide, etc.; nitrile-containing vinyl monomers such asacrylonitrile, methacrylonitrile, etc.; amide-containing vinyl monomerssuch as acrylamide, methacrylamide, etc.; vinyl esters such as vinylacetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinylcinnamate, etc.; alkenes such as ethylene, propylene, etc.; conjugateddienes such as butadiene, isoprene, etc.; vinyl chloride, vinylidenechloride, allyl chloride, and allyl alcohol. Those monomers may be usedeach independently or a plurality of them may be used.

In the above manner of expression, “(meth)acrylic acid”, for instance,means acrylic acid and methacrylic acid.

Preferred as the above vinyl polymer having at least one crosslinkablesilyl group from the physical characteristics viewpoint are(meth)acrylic polymers obtained by polymerizing using not less than 40%by weight of a (meth)acrylic monomer among the vinyl monomersspecifically mentioned above.

The molecular weight of said vinyl polymer having at least onecrosslinkable silyl group is not particularly restricted but ispreferably within the range of 500 to 100,000. When the molecular weightis below 500, the characteristics intrinsic in the vinyl polymer arehardly expressed. A molecular weight above 100,000 makes handlingdifficult.

The molecular weight distribution, namely the ratio (Mw/Mn) of weightaverage molecular weight (Mw) to number average molecular weight (Mn) asdetermined by gel permeation chromatography, of said vinyl polymerhaving at least one crosslinkable silyl group is not particularlyrestricted but, for suppressing the viscosity of the adhesive curablecomposition prepared by using said polymer to thereby facilitatehandling of said composition and for obtaining cured products havingsufficient physical properties, a narrow molecular weight distributionis preferred. Specifically, an Mw/Mn value of less than 1.8 ispreferred. Said value is more preferably not more than 1.7, still morepreferably not more than 1.6, still more preferably not more than 1.5,in particular not more than 1.4, most preferably not more than 1.3.

The method of synthesizing said vinyl polymer having at least onecrosslinkable silyl group is not particularly restricted but variousmethods may be used. From the viewpoint of versatility concerningmonomers and ease of control, however, the method comprising directlyintroducing a crosslinkable silyl group into the main chain by radicalpolymerization and the method comprising obtaining a vinyl polymerhaving a specific functional group convertible to a crosslinkable silylgroup by one to several reaction steps and then converting said specificfunctional group to a crosslinkable silyl group are preferred.

The techniques for radical polymerization to be used in synthesizing thevinyl polymer having a specific functional group, inclusive of acrosslinkable silyl group, may be classified into two groups; one is“ordinary radical polymerization” in which a monomer having a specificfunctional group and a vinyl monomer are merely copolymerized using anazo compound or a peroxide, for instance, as the polymerizationinitiator and the other is “controlled radical polymerization” by whichit is possible to introduce a specific functional group into the polymerat controlled sites, for example at terminal sites.

“Ordinary radical polymerization” is simple and easy to perform and mayalso be employed in the practice of the present invention. However, themonomer having a specific functional group can be introduced into thepolymer only in a random manner. When a polymer with a high degree offunctionalization is to be obtained, it is necessary to use said monomerin a considerably large amount. When the amount of said monomer issmall, the problem arises that the increases in the proportion ofpolymer molecules in which said specific functional group has not beenintroduced. There is another problem that a wide molecular weightdistribution results, hence only a polymer having high viscosity can beobtained.

“Controlled radical polymerization” methods can be further classifiedinto two: one is “chain transfer agent method” which comprises using achain transfer agent having a specific functional group to therebyobtain a functional group-terminated vinyl polymer, and the other is“living radical polymerization method” by which a polymer having amolecular weight almost as designed can be obtained as a result ofgrowing polymerization termini grow without undergoing termination orlike reactions.

The “chain transfer agent method” can give a polymer with a high degreeof functionalization and may also be used in the practice of the presentinvention. However, said method requires a fairly large amount of achain transfer agent as compared with the initiator and raiseseconomical problems, inclusive of a treatment-related problem. Like theabove “ordinary radical polymerization”, this method involves freeradical polymerization and, therefore, gives only a high viscositypolymer with a wide molecular weight distribution.

Differing from the above polymerization methods, the “living radicalpolymerization” proceeds at a high rate of polymerization and hardlyundergoes termination reactions and gives a polymer with a narrowmolecular weight distribution (polymer with an Mw/Mn value of about 1.1to 1.5) in spite of its being a mode of that radical polymerizationwhich is regarded as difficult to control because of tendency towardoccurrence of termination reactions such as radical-to-radical coupling.It is also possible to arbitrarily control the molecular weight byadjusting the monomer/initiator charge ratio.

The “living radical polymerization” method thus can give a low viscositypolymer with a narrow molecular weight distribution and, in addition,allows introduction of the specific functional group-containing monomerinto the polymer mostly at the desired sites and, therefore, ispreferred as the method of producing the above specific functionalgroup-containing vinyl polymer.

While the term “living polymerization”, in its narrower sense, meanspolymerization in which molecular chains grow while the termini thereofalways retain their activity, said term generally includes, within themeaning thereof, quasi-living polymerization in which terminallyinactivated molecules and terminally active molecules grow in a state ofequilibrium. The latter definition applies to the living polymerizationto be employed in the present invention.

Such “living radical polymerization” has recently been studied activelyby various groups of researchers. As examples, there may be mentioned,among others, the use of a cobalt-porphyrin complex as described in theJournal of the American Chemical Society, 1994, vol. 116, pages 7943 ff,the use of a radical capping agent such as a nitroxide compound asdescribed in Macromolecules, 1994, vol. 27, pages 7228 ff., and thetechnique of “atom transfer radical polymerization; ATRP” which uses anorganic halide or the like as the initiator and a transition metalcomplexes as the catalyst.

Among the “living radical polymerization” techniques, theabove-mentioned “atom transfer radical polymerization” technique has, inaddition to the above-mentioned advantageous features of “living radicalpolymerization”, advantages in that it gives a polymer having a halogenor the like, which is relatively advantageous to functional groupconversion, at the main chain termini and that the degree of freedom ininitiator and catalyst designing and, therefore, is preferred as themethod of producing the above-mentioned specific functionalgroup-containing vinyl polymer.

Said “atom transfer radical polymerization” is carried out using anorganic halide or halogenated sulfonyl compound or the like as theinitiator and a transition metal complex as the catalyst, and themonomers mentioned above, if necessary together with a solvent and/orthe like. This atom transfer radical polymerization is described, forexample, by Matyjaszewski et al. in the Journal of the American ChemicalSociety, 1995, vol. 117, pages 5614 ff.; Macromolecules, 1995, vol. 28,pages 7901 ff.; Science, 1996, vol. 272, pages 866 ff.; WO 96/30421 andWO 97/18247, and by Sawamoto et al. in Macromolecules, 1995, vol. 28,pages 1721 ff.

The organic halide to be used as the initiator in said “atom transferradical polymerization” is preferably an organic halide having a highlyreactive carbon-halogen bond, which specifically includes, among others,carbonyl compounds having a halogen at -position and compounds having ahalogen at benzyl-position.

The transition metal catalyst to be used as the catalyst in said “atomtransfer radical polymerization” is not particularly restricted butincludes, among others, complexes with an element of a group 7, 8, 9, 10or 11 of the periodic table as the central metal. As preferred examples,there may be mentioned complexes of copper having a valency of 0 (zero),monovalent copper, divalent ruthenium, divalent iron or divalent nickel.Among them, copper complexes are preferred. These may be used singly ortwo or more of them may be used in combination.

Said monovalent copper compounds are not particularly restricted butincludes, among others, cuprous chloride, cuprous bromide, cuprousiodide, cuprous cyanide, cuprous oxide and cuprous perchlorate. Whensuch a copper compound is used, a ligand, such as 2,2′-bipyridyl or aderivative thereof, 1,10-phenanthroline or a derivative thereof,tetramethyl-ethylenediamine, pentamethyldiethylenetriamine,hexamethyltris(2-aminoethyl)amine or a like polyamine, is added forincreasing the catalytic activity.

The tristriphenylphosphine complex of divalent ruthenium chloride[RuCl₂(PPh₃)₃] is also suited for use as the catalyst. When a rutheniumcompound is used, an aluminum alkoxide is added as an activator.Further, the bistriphenylphosphine complex of divalent iron[FeCl₂(PPh₃)₂], bistriphenylphosphine complex of divalent nickel[NiCl₂(PPh₃)₂] and bistributylphosphine complex of divalent nickel[NiBr₂(PBu₃)₂] are also suitable as the catalyst.

The solvent mentioned above is not particularly restricted but includes,among others, hydrocarbon solvents such as benzene and toluene; ethersolvents such as diethyl ether and tetrahydrofuran; halogenatedhydrocarbon solvents such as methylene chloride and chloroform; ketonesolvents such as acetone, methyl ethyl ketone and methyl isobutylketone; alcohol solvents such as methanol, ethanol, propanol,isopropanol, n-butyl alcohol and tert-butyl alcohol: nitrile solventssuch as acetonitrile, propionitrile and benzonitrile; ester solventssuch as ethyl acetate and butyl acetate; and carbonate solvents such asethylene carbonate and propylene carbonate. These may be used singly ortwo or more of them may be used combinedly.

Said “atom transfer radical polymerization” can be carried out withinthe range of 0 to 200° C. preferably within the range of roomtemperature to 150° C.

Now, several specific methods of synthesizing the above-mentioned vinylpolymer having at least one crosslinkable silyl group are describedbelow under (A) to (E). These, however, have no limitative meaning.

(A) Method comprising subjecting a vinyl polymer having at least onealkenyl group to addition reaction with a crosslinkable silyl-containinghydrosilane compound in the presence of a hydrosilylation catalyst;

(B) Method comprising reacting a vinyl polymer having at least onehydroxyl group with a compound having a crosslinkable silyl group and afunctional group capable of reacting with a hydroxyl group, for examplean isocyanato group;

(C) Method comprising subjecting a compound having a polymerizablealkenyl group and a crosslinkable silyl group, together with thepredetermined vinyl monomer(s), to reaction in the step of synthesizinga vinyl polymer by radical polymerization;

(D) Method comprising carrying out radical polymerization using acrosslinkable silyl-containing chain transfer agent;

(E) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with a crosslinkablesilyl-containing stabilized carbanion.

The method of synthesizing the vinyl polymer having at least one alkenylgroup, which is to be used in the above synthetic method (A), is notparticularly restricted but may include the following methods (A-a) to(A-j), among others:

(A-a) Method comprising subjecting a compound having a polymerizablealkenyl group and an alkenyl group having low polymerizability, namely acompound represented by the general formula (2) shown below, togetherwith the predetermined vinyl monomer(s), to reaction in the step ofsynthesizing a vinyl polymer by radical polymerization:

H₂C═C(R³)—R⁴—R⁵—C(R⁶)═CH₂  (2)

 wherein R³ represents a hydrogen atom or a methyl group; R⁴ represents—C(O)O— or an o-, m- or p-phenylene group; R⁵ represents a direct bondor a divalent organic group containing 1 to 20 carbon atoms, which mayoptionally contain one or more ether bonds; and R⁶ represents a hydrogenatom, an alkyl group containing 1 to 10 carbon atoms, an aryl groupcontaining 6 to 10 carbon atoms or an aralkyl group containing 7 to 10carbon atoms.

The time for submitting the above compound having a polymerizablealkenyl group and a low-polymerizable alkenyl group to reaction is notparticularly restricted but, when rubber-like properties are expected ofthe polymer to be obtained, it is preferred that living radicalpolymerization be employed and that said compound be subjected toreaction as a second monomer component at the final stage ofpolymerization or after completion of the reaction of the vinyl monomer.

(A-b) Method comprising subjecting a compound having at least twolow-polymerizable alkenyl groups, such as 1,5-hexadiene, 1,7-octadieneor 1,9-decadiene, to reaction as a second monomer component at the finalstage of polymerization or after completion of the reaction of thepredetermined vinyl monomer in synthesizing a vinyl polymer by livingradical polymerization.

The following methods (A-c) to (A-f) are methods of preparing vinylpolymers having at least one alkenyl group mentioned above from a vinylpolymer having at least one highly reactive carbon-halogen bond, whichin turn can be prepared by the methods (E-a) and (E-b) to be mentionedlater herein.

(A-c) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with an alkenyl-containingorganometallic compound, such as allyltributyltin or allyltrioctyltin,to thereby substitute an alkenyl-containing group for the halogen.

(A-d) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with an alkenyl-containingstabilized carbanion represented by the general formula (3) shown below,to thereby substitute an alkenyl-containing group for the halogen:

M⁺C⁻(R⁷)(R⁸)—R⁹—C(R⁶)═CH₂  (3)

 wherein R⁶ is as defined above; R⁷ and R⁸ each represents anelectron-withdrawing group serving to stabilize the carbanion C⁻ or oneof them represents such electron-withdrawing group and the other is ahydrogen atom, an alkyl group containing 1 to 10 carbon atoms or aphenyl group; R⁹ represents a direct bond or a divalent organic groupcontaining 1 to 10 carbon atoms, which may optionally contain one ormore ether bonds; and M⁺ represents an alkali metal ion or a quaternaryammonium ion. Preferred as the electron-withdrawing group represented byR⁷ and/or R⁸ are —CO₂R, —C(O)R or —CN, in which R represents a hydrogenatom, an alkyl group containing 1 to 10 carbon atoms, an aryl groupcontaining 6 to 10 carbon atoms or an aralkyl group containing 7 to 10carbon atoms.

(A-e) Method comprising preparing an enolate anion by reacting a vinylpolymer having at least one highly reactive carbon-halogen bond with anelementary metal, such as zinc, or an organometallic compound and thenreacting the enolate anion with an alkenyl-containing electrophiliccompound, such as alkenyl-containing compound having a leaving groupsuch as a halogen atom or an acetyl group, an alkenyl-containingcarbonyl compound, an alkenyl-containing isocyanate compound or analkenyl-containing acid halide compound.

(A-f) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with an alkenyl-containing oxy anionrepresented by the general formula (4) shown below or analkenyl-containing carboxylate anion represented by the general formula(5) shown below, to thereby substitute an alkenyl-containing group forthe above halogen:

H₂C═C(R⁶)—R¹⁰—O⁻M⁺  (4)

 wherein R⁶ and M⁺ are as defined above and R¹⁰ represents a divalentorganic group containing 1 to 20 carbon atoms, which may optionallycontain one or more ether bonds;

H₂C═C(R⁶)—R¹¹—C(O)O⁻M⁺  (5)

 wherein R⁶ and M⁺ are as defined above and R¹¹ represents a direct bondor a divalent organic group containing 1 to 20 carbon atoms, which maycontain one or more ether bonds.

The above-mentioned vinyl polymer having at least one alkenyl group canbe obtained also from the corresponding vinyl polymer having at leastone hydroxyl group. The specific method therefor is not particularlyrestricted but includes, among others, the methods (A-g) to (A-j)mentioned below. Said vinyl polymer having at least one hydroxyl groupcan be prepared by the methods (B-a) to (B-i) to be mentioned laterherein.

(A-g) Method comprising reacting a vinyl polymer having at least onehydroxyl group with a base such as sodium methoxide and then reactingthe resulting polymer with an alkenyl-containing halide such as allylchloride.

(A-h) Method comprising reacting a vinyl polymer having at least onehydroxyl group with an alkenyl-containing isocyanate compound such asallyl isocyanate.

(A-i) Method comprising reacting a vinyl polymer having at least onehydroxyl group with an alkenyl-containing acid halide, such as(meth)acryloyl chloride, in the presence of a base such as pyridine.

(A-j) Method comprising reacting a vinyl polymer having at least onehydroxyl group with an alkenyl-containing carboxylic acid, such asacrylic acid, in the presence of an acid catalyst.

In synthesizing the above-mentioned vinyl polymer having at least onealkenyl group, when no halogen atom is directly involved in alkenylgroup introduction, as in the case of the above methods (A-a) and (A-b),the use of living radical polymerization is preferred and, in that case,the method (A-b) is more preferred because of ease of control.

On the contrary, where alkenyl group introduction is effected byconversion of the halogen of a vinyl polymer having at least one highlyreactive carbon-halogen bond, as in the case of the above methods (A-c)to (A-f), the use of a vinyl polymer having at least one highly reactiveterminal carbon-halogen bond, which can be prepared by radicalpolymerization (atom transfer radical polymerization) using an organichalide or a halogenated sulfonyl compound as the initiator and atransition metal complex as the catalyst is preferred. In that case, themethod (A-f) is more preferred because of each of control.

The crosslinkable silyl-containing hydrosilane compound to be used inthe above synthetic method (A) is not particularly restricted butincludes, among others, compounds represented by the following generalformula (6):

H—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (6)

wherein R¹, R², a, b, m and Y are as defined above.

Among these, compounds represented by the following general formula (7)are preferred because of ready availability:

H—Si(R²)_(3-a)(Y)_(a)  (7)

wherein R², Y and a are as defined above.

In causing the above crosslinkable silyl-containing hydrosilane compoundto add to the alkenyl group of the above-mentioned polymer by the abovesynthetic method (A), a transition metal catalyst is generally used asthe hydrosilylation catalyst.

Said transition metal catalyst is not particularly restricted butincludes, among others, elementary platinum; solid platinum dispersedand supported on a carrier such as alumina, silica or carbon black;chloroplatinic acid; complexes of chloroplatinic acid with an alcohol,aldehyde, ketone or the like; platinum-olefin complexes andplatinum(0)-divinyl-tetramethyldisiloxane complex; compounds other thanplatinum compounds, such as RhCl(PPh₃)₃, RhCl₃, RuCl₃, IrCl₃, FeCl₃,AlCl₃, PdCl₂.H₂O, NiCl₂ and TiCl₄. These may be used singly or two ormore of them may be used combinedly.

The method of synthesizing the vinyl polymer having at least onehydroxyl group, which is to be used in the above synthetic method (B) orin any of the above methods (A-g) to (A-j), is not particularlyrestricted but includes, among others, the methods (B-a) to (B-i)mentioned below.

(B-a) Method comprising subjecting a compound having a polymerizablealkenyl group and a hydroxyl group as represented by the general formula(8) shown below, together with the predetermined vinyl monomer, toreaction in the step of synthesizing the vinyl polymer by radicalpolymerization:

H₂C═C(R³)—R⁴—R⁵—OH  (8)

 wherein R³, R⁴ and R⁵ are as defined above.

The time for subjecting said compound having a polymerizable alkenylgroup and a hydroxyl group to reaction is not particularly restrictedbut, when rubber-like properties are expected of the polymer to beobtained, it is preferred that living radical polymerization be employedand that said compound be added as a second monomer component at thefinal stage of polymerization or after completion of the reaction of thepredetermined vinyl monomer.

(B-b) Method comprising subjecting an alkenyl alcohol, such as10-undecenol, 5-hexenol or allyl alcohol, to reaction as a secondmonomer component at the final stage of polymerization or aftercompletion of the predetermined vinyl monomer in synthesizing the vinylpolymer by living radical polymerization.

(B-c) Method comprising subjecting the above vinyl monomer to radicalpolymerization using a large amount of a hydroxyl-containing chaintransfer agent, such as a hydroxyl-containing polysulfide, as disclosedin Japanese Kokai Publication Hei-5-262808.

(B-d) Method comprising subjecting the above vinyl monomer to radicalpolymerization using hydrogen peroxide or a hydroxyl-containinginitiator, as disclosed in Japanese Kokai Publication Hei-6-239912 orJapanese Kokai Publication Hei-8-283310.

(B-e) Method comprising subjecting the above vinyl monomer to radicalpolymerization using an alcohol in excess, as disclosed in JapaneseKokai Publication Hei-6-116312.

(B-f) Method comprising subjecting the halogen atom of a vinyl polymerhaving at least one highly reactive carbon-halogen bond to hydrolysis orreaction with a hydroxyl-containing compound to thereby terminallyintroduce a hydroxyl group.

(B-g) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with a hydroxyl-containingstabilized carbanion represented by the general formula (9) shown belowto thereby substitute a hydroxyl-containing substituent for the halogenatom:

M⁺C⁻(R⁷)(R⁸)—R⁹—OH  (9)

 wherein R⁷, R⁸ and R⁹ are as defined above. As the electron-withdrawinggroup represented by R⁷ or R⁸, —CO₂R, —C(O)R and —CN are preferred (Rbeing as defined above).

(B-h) Method comprising preparing an enolate anion by reacting a vinylpolymer having at least one highly reactive carbon-halogen bond with anelementary metal, such as zinc, or an organometallic compound and thenreacting said enolate anion with an aldehyde or ketone.

(B-i) Method comprising reacting a vinyl polymer having at least onehighly reactive carbon-halogen bond with a hydroxyl-containing oxy anionrepresented by the general formula (10) shown below or ahydroxyl-containing carboxylate anion represented by the general formula(11) shown below to thereby substitute a hydroxyl-containing group forthe halogen.

HO—R¹⁰—O⁻M⁺  (10)

 wherein R¹⁰ and M⁺ are as defined above;

HO—R¹¹—C(O)O⁻M⁺  (11)

 wherein R¹¹ and M⁺ are as defined above.

In synthesizing the above-mentioned vinyl polymer having at least onehydroxyl group, when no halogen atom is involved in introducing thehydroxyl group, as in the above methods (B-a) to (B-e), living radicalpolymerization is preferably used. In that case, the method (B-b) ismore preferred because of ease of control.

In cases where hydroxyl group introduction is effected by converting thehalogen of a vinyl polymer having at least one highly reactivecarbon-halogen bond, as in the above methods (B-f) to (B-i), the use ispreferred of a vinyl polymer having at least one highly reactiveterminal carbon-halogen bond, which is obtained by radicalpolymerization (atom transfer radical polymerization) using an organichalide or halogenated sulfonyl compound as the initiator and atransition metal complex as the catalyst. In that case, the method (B-i)is preferred because of ease of control.

The compound having a crosslinkable silyl group and a functional groupcapable of reacting with a hydroxyl group, for example an isocyanatogroup, is not particularly restricted but includes, among others,γ-isocyanatopropyltrimethoxysilane,γ-isocyanatopropylmethyldimethoxysilane andγ-isocyanato-propyltriethoxysilane. These may be used singly or two ormore of them may be used combinedly.

In carrying out the reaction in the above synthetic method (B), it isalso possible to use a per se known catalyst for urethane formationreaction, if necessary.

The compound having a polymerizable alkenyl group and a crosslinkablesilyl group, which is to be used in the above synthetic method (C), isnot particularly restricted but includes, among others, compoundsrepresented by the general formula (12) shown below, such astrimethoxysilylpropyl (meth)acrylate and methyldimethoxysilylpropyl(meth)acrylate:

H₂C═C(R³)—R⁴—R¹²—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (12)

wherein R¹, R², R³, R⁴, Y, a, b and m are as defined above and R¹²represents a direct bond or a divalent organic group containing 1 to 20carbon atoms, which may contain one or more ether bonds. These compoundsmay be used singly or two or more of them may be used combinedly.

In the above synthetic method (C), the time for subjecting said compoundhaving a polymerizable alkenyl group and a crosslinkable silyl group toreaction is not particularly restricted but, when rubber-like propertiesare expected of the polymer to be obtained, it is preferred that, inliving radical polymerization, said compound be subjected to reaction asa second monomer component at the last stage of polymerization or aftercompletion of the reaction of the predetermined vinyl monomer.

The crosslinkable silyl-containing chain transfer agent to be used incarrying out the above synthetic method (D) is not particularlyrestricted but includes crosslinkable silyl-containing mercaptans andcrosslinkable silyl-containing hydrosilanes, as disclosed in JapaneseKokoku Publication Hei-3-14068 or Japanese Kokoku PublicationHei-4-55444.

The method of synthesizing the vinyl polymer having at least one highlyreactive carbon-halogen bond to be used in the above synthetic method(E) and further in the above methods (A-c) to (A-f) and (B-f) to (B-i)is not particularly restricted but includes, among others, the methods(E-a) and (E-b) mentioned below.

(E-a) Method disclosed in Japanese Kokai Publication Hei-4-132706 andcomprising carrying out radical polymerization using a halide, such ascarbon tetrachloride, ethylene chloride, carbon tetrabromide ormethylene bromide, as the chain transfer agent (chain transfer agentmethod).

(E-b) Method involving the above-mentioned atom transfer radicalpolymerization using an organic halide as the initiator and a transitionmetal complex as the catalyst.

The crosslinkable silyl-containing stabilized carbanion to be used inthe above synthetic method (E) is not particularly restricted butincludes, among others, compounds represented by the following generalformula (13):

M⁺C⁻(R⁷)(R⁸)—R¹³—C(H)(R¹⁴)—CH₂—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (13)

wherein R¹, R², R⁷, R⁸, Y, a, b and m are as defined above; R¹³represents a direct bond or a divalent organic group containing 1 to 10carbon atoms, which may contain one or more ether bonds; and R¹⁴represents a hydrogen atom, an alkyl group containing 1 to 10 carbonatoms, an aryl group containing 6 to 10 carbon atoms or an aralkyl groupcontaining 7 to 10 carbon atoms. Preferred as the electron-withdrawinggroup represented by R⁷ or R⁸ are —CO₂R, —C(O)R and —CN, R being asdefined above.

In cases where the adhesive curable composition of the present inventionis to be used in an application field requiring rubber-like properties,the above-mentioned vinyl polymer having at least one crosslinkablesilyl group is preferably one having at least one crosslinkable silylgroup at a molecular chain terminus so that the molecular weight betweencrosslinking sites, which exerts a great influence on rubber elasticity,may be increased. It is more preferred that said polymer have allcrosslinkable silyl groups at molecular chain termini.

Therefore, the vinyl polymer having at least one hydroxyl group orhalogen atom or alkenyl group, which is to be used in synthesizing thepolymer having at least one crosslinkable silyl group, is preferably onehaving such functional group or atom at a molecular chain terminus.

Certain methods are disclosed in Japanese Kokoku PublicationHei-3-14068, Japanese Kokoku Publication Hei-4-55444 and Japanese KokaiPublication Hei-6-211922, among others, for producing said vinyl polymerhaving at least one crosslinkable silyl group at a molecular chainterminus, in particular such a (meth)acrylic polymer. However, thesemethods use the above-mentioned “chain transfer agent method” andtherefore, while the polymer obtained has a relatively high proportionof crosslinkable silyl groups occurring at a molecular chain terminus,it is a problem that the molecular weight distribution value representedby Mw/Mn is generally as high as not less than 2, hence said polymer hasan increased viscosity. Therefore, for obtaining such vinyl polymerhaving a narrow molecular weight distribution, a low viscosity and ahigh proportion of crosslinkable silyl groups occurring at a molecularchain terminus, the above-mentioned “living radical polymerization” ispreferably employed.

For obtaining such vinyl polymer having at least one crosslinkable silylgroup at a molecular chain terminus by the “atom transfer radicalpolymerization” technique, which is preferred among the “living radicalpolymerization” techniques, an organic halide or halogenated sulfonylcompound having two or more initiation sites is preferably used as theinitiator. The thus-obtained vinyl polymer having at least one highlyreactive carbon-halogen bond at a molecular chain terminus can readilybe converted to a vinyl polymer having at least one crosslinkable silylgroup at a molecular chain terminus by the methods mentioned above.

Said organic halide or halogenated sulfonyl compound having two or moreinitiation sites is not particularly restricted but includes thosecompounds which are represented by the general formulas (14-1) to(14-11) and (15-1) to (15-10) shown below. These may be used singly ortwo or more of them may be used in combination.

In the above formulas, R represents an alkyl group containing 1 to 20carbon atoms, an aryl group containing 6 to 20 carbon atoms or anaralkyl group containing 7 to 20 carbon atoms; C₆H₄ represents aphenylene group; n represents an integer of 0 to 20; and X represents achlorine, bromine or iodine atom.

For obtaining a vinyl polymer having crosslinkable silyl groups at bothmolecular chain termini, the method comprising carrying out theabove-mentioned “atom transfer radical polymerization” using an organichalide or halogenated sulfonyl compound having two initiation sites aswell as the method comprising a crosslinkable silyl-containing organichalide are preferred.

Said crosslinkable silyl-containing organic halide is not particularlyrestricted but includes, among others, compounds represented by thefollowing general formula (16) or (17):

R¹⁵R¹⁶C(X)—R¹⁷—R¹⁸—C(H)(R¹⁹)CH₂—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (16)

wherein R¹, R², a, b, m, X and Y are as defined above; R¹⁵ and R¹⁶ arethe same or different and each represents a hydrogen atom, an alkylgroup containing 1 to 20 carbon atoms, an aryl group containing 6 to 20carbon atoms or an aralkyl group containing 7 to 20 carbon atoms or R¹⁵and R¹⁶ are bound together at each other end; R¹⁷ represents —C(O)O—,—C(O)— or an o-, m- or p-phenylene group; R¹⁸ represents a direct bondor a divalent organic group containing 1 to 10 carbon atoms, which maycontain one or more ether bonds; and R¹⁹ represents a hydrogen atom, analkyl group containing 1 to 10 carbon atoms, an aryl group containing 6to 10 carbon atoms or an aralkyl group containing 7 to 10 carbon atoms;

(R²)_(3-a)(Y)_(a)Si—[OSi(R¹)_(2-b)(Y)_(b)]_(m)—CH₂—C(H)(R¹⁹)—R¹⁸—C(R¹⁵)(X)—R¹⁷—R¹⁶  (17)

wherein R¹, R², R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, a, b, m, X and Y are as definedabove.

When the above-mentioned “atom transfer radical polymerization” iscarried out using the above-mentioned crosslinkable silyl-containingorganic halide as the initiator, a vinyl polymer having thecrosslinkable silyl group at one terminus and the highly reactivecarbon-halogen bond at the other terminus is obtained. By converting thehalogen atom at the termination terminus of said vinyl polymer to acrosslinkable silyl-containing substituent, for example, by the methodsmentioned above, it is possible to obtain a vinyl polymer havingcrosslinkable silyl groups at both molecular chain termini.

It is also possible to obtain such vinyl polymer having crosslinkablesilyl groups at both molecular chain termini by coupling one halogenterminus of the above vinyl polymer to another halogen terminal thereofusing a compound having two or more same or different functional groupscapable of substituting the termination end halogen atom.

Said compound having two or more same or different functional groupscapable of substituting the termination end halogen atom is notparticularly restricted but includes, among others, polyols, polyamines,polycarboxylic acids, polythiols, and salts thereof; and alkali metalsulfides.

When, in the above “atom transfer radical polymerization”, analkenyl-containing organic halide is used as the initiator, a vinylpolymer having the alkenyl group at one terminus and the halogen atom atthe other terminus is obtained. By converting the terminal halogen atomto an alkenyl-containing substituent by the methods mentioned above, forinstance, it is possible to obtain a vinyl polymer having an alkenylgroup at both molecular chain termini. By converting these alkenylgroups within this vinyl polymer to crosslinkable silyl groups by themethods mentioned above, for instance, it is possible to obtain a vinylpolymer having a crosslinkable silyl group at both molecular chaintermini.

Said vinyl polymer having at least one crosslinkable silyl group at amolecular chain terminus can be prepared by an appropriate combinationof the methods mentioned above. As typical examples, the followingsynthetic processes a and b may be mentioned.

Synthetic Process a

A synthetic process comprising (1) synthesizing a halogen-terminatedvinyl polymer by subjecting a vinyl monomer to radical polymerizationusing an organic halide or halogenated sulfonyl compound as theinitiator and a transition metal complex as the catalyst, (2) reactingsaid polymer with an alkenyl-containing oxy anion for substitution ofthe terminal halogen, to give an alkenyl-terminated vinyl polymer and(3) allowing a crosslinkable silyl-containing hydrosilane compound toadd to the terminal alkenyl group of said polymer to thereby convertsaid alkenyl group to a crosslinkable silyl-containing substituent.

Synthetic Process b

A synthetic process comprising (1) synthesizing a vinyl polymer bysubjecting a vinyl monomer to living radical polymerization, (2) thenreacting said polymer with a compound having at least two alkenyl groupswith low polymerizability to thereby synthesize an alkenyl-terminatedvinyl polymer and (3) converting the terminal alkenyl groups tocrosslinkable silyl-containing substituents by allowing a crosslinkablesilyl-containing hydrosilane compound to add to terminal alkenyl groupsof said polymer.

The adhesive curable composition of the present invention comprises thevinyl polymer having at least one crosslinkable silyl group as obtainedin the above manner. For curing said composition, a condensationcatalyst may be incorporated therein.

Said condensation catalyst is not particularly restricted but includes,among others, titanate esters such as tetrabutyl titanate andtetrapropyl titanate; organotin compounds such as dibutyltin dilaurate,dibutyltin diacetylacetonate, dibutyltin maleate, dibutyltin diacetate,dibutyltin dimethoxide, reaction products derived from dibutyltin oxideand a carboxylic acid ester, carboxylic acid or hydroxyl-containingcompound, tin octylate and tin naphthenate; organoaluminum compoundssuch as aluminum trisacetylacetonate, aluminum tris(ethyl acetoacetate)and diisopropoxyaluminum ethyl acetoacetate; organozirconium compoundssuch as zirconium tetraacetylacetonate, zirconium tetraisopropoxide andzirconium tetrabutoxide; organolead compounds such as lead octylate;amine compounds such as butylamine, octylamine, dibutylamine,monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine,triethylenetetramine, oleylamine, octylamine, cyclohexylamine,benzylamine, diethylaminopropylamine, xylylenediamine,triethylenediamine, guanidine, diphenylguanidine,2,4,6-tris(dimethylaminomethyl)phenol, morpholine, N-methylmorpholineand 1,3-diazabicyclo[5.4.6]-undecene-7, and carboxylic acid saltsthereof; reaction products from or mixtures of an amine compound and anorganotin compound, such as a reaction product from or a mixture oflaurylamine and tin octylate; low-molecular polyamide resins obtainedfrom an excess of a polyamine and a polybasic acid; reaction productsfrom an excess of a polyamine and an epoxy compound; amino-containingsilane coupling agents such as γ-aminopropyltrimethoxysilane andN-(β-aminoethyl)-aminopropylmethyldimethoxysilane; and like knownsilanol condensation catalysts. These may be used singly or two or moreof them may be used combinedly.

The addition amount of said condensation catalyst is not particularlyrestricted but is preferably within the range of, for example 0 to 10parts by weight per 100 parts by weight of the vinyl polymer having atleast one crosslinkable silyl group. While it is not always necessary toincorporate the above condensation catalyst, it is preferred that saidcondensation catalyst is incorporated when the vinyl polymer having atleast one crosslinkable silyl group has an alkoxy group as thehydrolyzable group, since, in that case, the rate of curing is slow.

In the adhesive curable composition of the present invention, the vinylpolymer having at least one crosslinkable silyl group itself hasadhesiveness to glass, ceramics other than glass, and metals, amongothers, and can be adhered to a wide variety of materials by usingvarious primers, so that the use of an adhesion promoter is not alwaysnecessary. For attaining stable adhesion to various substrates, parts,supports and adherends, however, the use of an adhesion promoter ispreferred.

Said adhesion promoter is not particularly restricted but includes,among others, resol type or novolak type phenolic resins obtained by thereaction of a phenol compound, such as phenol, cresol, xylenol,resorcinol, alkylphenol, or modified phenol (e.g. cashew nutoil-modified phenol, tall oil-modified phenol), with an aldehydecompound such as formaldehyde or paraformaldehyde; sulfur; epoxy resinssuch as bisphenol A-based epoxy resins, bisphenol F-based epoxy resins,novolak type epoxy resins, bisphenol A-propylene oxide adduct-derivedglycidyl ether type epoxy resins and hydrogenated bisphenol A-basedepoxy resins; alkyl titanates such as tetrabutyl titanate; aromaticpolyisocyanates such as tolylene diisocyanate anddiphenylmethanediisocyanate; amino- and crosslinkable silyl-containingcompounds such as γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane,N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane,N-(β-aminoethyl)-γ-aminopropyltriethoxysilane andN-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane; epoxy- andcrosslinkable silyl-containing compounds such asγ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane andγ-glycidoxy-propylmethyldimethoxysilane; mercapto- and crosslinkablesilyl-containing compounds such as γ-mercaptopropyltrimethoxysilane,γ-mercaptopropyl-triethoxysilane andγ-mercaptopropylmethyldimethoxysilane; isocyanato- and crosslinkablesilyl-containing compounds such as γ-isocyanatopropyltrimethoxysilane,γ-isocyanatopropyltriethoxysilane andγ-isocyanatopropylmethyldimethoxysilane; reaction products from theabove amino- and crosslinkable silyl-containing compounds and the aboveepoxy- and crosslinkable silyl-containing compounds or isocyanato- andcrosslinkable silyl-containing compounds; reaction products from a(meth)acryloxy- and crosslinkable silyl-containing compounds, such asγ-(meth) acryloxypropyltrimethoxysilane,γ-(meth)acryloxypropyltriethoxysilane orγ-(meth)acryloxypropylmethyldimethoxysilane, and the above amino- andcrosslinkable silyl-containing compounds; and the like. These may beused singly or two or more of them may be used in combination.

Preferred among those mentioned above from the viewpoint of relativelyeasy control of physical properties and adhesiveness are amino- andcrosslinkable silyl-containing compounds, epoxy- and crosslinkablesilyl-containing compounds, mercapto- and crosslinkable silyl-containingcompounds, isocyanato- and crosslinkable silyl-containing compounds,reaction products from an amino- and crosslinkable silyl-containingcompound and an epoxy- and crosslinkable silyl-containing compound orisocyanato- and crosslinkable silyl-containing compound, reactionproducts from a (meth)acryloxy- and crosslinkable silyl-containingcompound and an amino- and crosslinkable silyl-containing compound, andlike crosslinkable silyl-containing compounds having an organic grouphaving at least one atom selected from among nitrogen, oxygen and sulfuratoms. More preferred because of high adhesiveness are crosslinkablesilyl-containing compounds having a nitrogen atom-containing organicgroup which is an amino or isocyanato group or a group formed uponreaction thereof.

Said adhesion promoter is preferably used in an amount within the rangeof 0.01 to 20 parts by weight per 100 parts by weight of the vinylpolymer having at least one crosslinkable silyl group. When the amountis less than 0.01 part by weight, the adhesion improving effect canhardly be produced. When it is in excess of 20 parts by weight, thephysical properties of the cured product may adversely be affected. Amore preferred range is 0.1 to 10 parts by weight and a still morepreferred range is 0.5 to 5 parts by weight.

By incorporating a physical property modifier in the adhesive curablecomposition of the present invention, it is possible to control thephysical properties of the cured product by increasing the hardness uponcuring or by conversely reducing the hardness and increasing theelongation.

Said physical property modifier is not particularly restricted butincludes, among others, alkylalkoxysilanes such asmethyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilaneand n-propyltrimethoxysilane; alkylisopropenoxysilanes such asdimethyldiisopropenoxysilane, methyltriisopropenoxysilane and-glycidoxypropylmethyldiisopropenoxysilane; silane coupling agents suchas vinyltrimethoxysilane and vinylmethyldimethoxysilane; siliconevarnishes; and polysiloxanes. These may be used singly or two or more ofthem may be used combinedly.

The above physical property modifier is preferably used in an amountwithin the range of 0 to 20 parts by weight per 100 parts by weight ofthe vinyl polymer having at least one crosslinkable silyl group.

By incorporating a curability modifier in the adhesive curablecomposition of the present invention, it is possible to raise or reducethe rate of curing and, by incorporating a storage stability improver,it is possible to suppress viscosity increase during storage. Saidcurability modifier and storage stability improver are not particularlyrestricted but include, among others, alcohols such as methanol andethanol; ortho esters such as methyl orthoformate; crosslinkablesilyl-containing compounds such as tetraethoxysilane,methyltrimethoxysilane and vinyltrimethoxysilane; and carboxylic acidssuch as 2-ethyhexanoic acid. Where required, these may be used singly ortwo or more of them may be used combinedly. Said curability modifier andstorage stability improver are preferably used in an amount within therange of 0 to 20 parts by weight per 100 parts by weight of the vinylpolymer having at least one crosslinkable silyl group.

In the adhesive curable composition of the present invention, there mayfurther be incorporated according to need, in addition to the aboveingredients, one or more additives selected from among various fillerssuch as silica, carbon black and calcium carbonate; variousplasticizers, for example aromatic dibasic acid esters such asdi(2-ethylhexyl) phthalate, nonaromatic dibasic acid esters such asdioctyl adipate, polyethers such as polypropylene glycol and acrylicoligomers; various solvents such as toluene and methyl ethyl ketone;various silane coupling agents; various modifiers such as crosslinkablesilyl-containing polysiloxanes; rheology modifiers such as polyamidewaxes, hydrogenated castor oil and metal soaps; surface characteristicsand/or weathering resistance improvers for ultraviolet-curable resins,oxygen-curable resins and the like; colorants, such as pigments anddyes; antioxidants, ultraviolet absorbers, light stabilizers, flameretardants and so forth.

The adhesive curable composition of the present invention canjudiciously be used as a sealing composition.

When the adhesive curable composition of the present invention is usedas a sealing composition, a filler may be incorporated therein to modifythe mechanical properties.

Said filler is not particularly restricted but includes, among others,reinforcing fillers such as fumed silica, precipitated silica, silicicanhydride, hydrous silicic acid and carbon black; fillers such ascalcium carbonate, magnesium carbonate, diatomaceous earth, calcinedclay, clay, talc, titanium oxide, bentonite, organic bentonite, ferricoxide, zinc oxide, activated zinc white and shirasu balloons; andfibrous fillers such as asbestos, glass fiber and filaments. These maybe used singly or two or more of them may be used combinedly.

For obtaining high strength cured products using the above fillers, theuse of fumed silica, precipitated silica, silicic anhydride, hydroussilicic acid, carbon black, finely divided surface-treated calciumcarbonate, calcined clay, clay, activated zinc white or the like as thefiller is preferred. In that case, said filler is used in an amountwithin the range of 1 to 200 parts by weight per 100 parts by weight ofthe vinyl polymer having at least one crosslinkable silyl group.

On the other hand, for obtaining low-strength, high-elongation curedproducts, the use of titanium oxide, calcium carbonate, talc, ferricoxide, zinc oxide, shirasu balloons or the like is preferred. In thatcase, the filler is used in an amount within the range of 1 to 200 partsby weight per 100 parts by weight of the vinyl polymer having at leastone crosslinkable silyl group.

For use as a sealing composition, a plasticizer may be incorporated tomodify the physical properties and viscosity.

Said plasticizer is not particularly restricted but includes, amongothers, phthalate esters such as dibutyl phthalate, diheptyl phthalate,di(2-ethylhexyl)phthalate, diisodecyl phthalate and butyl benzylphthalate; nonaromatic dibasic acid esters such as dioctyl adipate anddioctyl sebacate; polyalkylene glycol esters such as diethylene glycoldibenzoate and triethylene glycol dibenzoate; phosphate esters such astricresyl phosphate and tributyl phosphate; polyethylene glycol,polypropylene glycol, and polyethers derived therefrom by conversion ofthe hydroxyl groups; chlorinated paraffins; and hydrocarbon oils such asalkyldiphenyls and partially hydrogenated terphenyl. These may be usedsingly or two or more of them may be used combinedly. Incorporationthereof is not always necessary, however. The plasticizer may beincorporated beforehand in the step of polymer production.

The plasticizer is preferably incorporated in an amount of 0 to 100parts by weight per 100 parts by weight of the vinyl polymer having atleast one crosslinkable silyl group.

By mixing up all components and ingredients, said sealing compositionmay be prepared as a one-component formulation, which is stored intightly closed containers and, when applied, it absorbs moisture in theair and is thereby cured. It is also possible to prepare saidcomposition as a two-component formulation, namely a curing agentcomposition, which is obtained by separately prepared by compounding acuring catalyst, filler, plasticizer and water, for instance, and mixingup the above components prior to use. However, a one-componentformulation is preferred because of ease of handling and lesspossibility of making mistakes in application.

The adhesive curable composition of the present invention canjudiciously be used as a pressure sensitive adhesive composition aswell.

In cases where the adhesive curable composition of the present inventionis used as a pressure sensitive adhesive composition, a tackifier resinmay be added, if necessary, although the addition thereof is not alwaysnecessary since said composition comprises the vinyl polymer as the maincomponent.

Said tackifier resin is not particularly restricted but includes, amongothers, phenolic resins, modified phenolic resins,cyclopentadiene-phenol resins, xylene resins, chroman resins, petroleumresins, terpene resins, terpene-phenol resins, and rosin ester resins.These may by used singly or two or more of them may be used combinedly.

A solvent may be added to the above pressure sensitive adhesivecomposition for workability adjustment. Said solvent is not particularlyrestricted but includes, among others, aromatic hydrocarbon solventssuch as toluene and xylene; ester solvents such as ethyl acetate, butylacetate, amyl acetate and cellosolve acetate; and ketone solvents suchas methyl ethyl ketone, methyl isobutyl ketone and diisobutyl ketone.Said solvent may be the one used in the step of producing theabove-mentioned polymer.

Said pressure sensitive adhesive composition can be applied in adhesiveproducts such as adhesive tapes, sheets, labels and foils. For producingsuch adhesive products using said pressure sensitive adhesivecomposition, said pressure sensitive adhesive composition is applied, insolvent type, emulsion type or hot melt type form, to substratematerials such as films made of a synthetic resin or modified naturalproduct, paper, various kinds of cloth, metal foils, metallized plasticfoils, asbestos, and glass fiber cloth and the coatings are then exposedto moisture or water and allowed to stand for curing at roomtemperature, or heated for curing.

The adhesive curable composition of the present invention can further beused as a paint composition.

On that occasion, the vinyl polymer having at least one crosslinkablesilyl group is preferably synthesized by the above-mentioned syntheticmethod (C) which comprises subjecting a compound having a polymerizablealkenyl group and a crosslinkable silyl group as represented by theabove general formula (12) to reaction in the step of synthesizing thevinyl polymer by radical polymerization, since said method of productionis simple and easy to carry out and makes it possible to attain a highsolid content in the paint composition.

Among the compounds having a polymerizable alkenyl group and acrosslinkable silyl group, those compounds in which the crosslinkablesilyl group is an alkoxysilyl group are preferred from the viewpoint ofcost and safety. Such compounds are not particularly restricted butinclude, among others, CH₂═CHCO₂(CH₂)₃Si(OCH₃)₃,CH₂═CHCO₂(CH₂)₃Si(CH₃)(OCH₃)₂, CH₂═C(CH₃)CO₂(CH₂)₃Si(OCH₃)₃,CH₂═C(CH₃)CO₂(CH₂)₃Si(CH₃)(OCH₃)₂, CH₂═CHCO₂(CH₂)₃Si(OC₂H₅)₃,CH₂═CHCO₂(CH₂)₃Si(CH₃)(OC₂H₅)₂, CH₂═C(CH₃)CO₂(CH₂)₃Si(OC₂H₅)₃,CH₂═C(CH₃)CO₂(CH₂)₃Si(CH₃)(OC₂H₅)₂, CH₂═CHCO₂(CH₂)₃Si(OC₂H₅)₃,CH₂═CHCO₂(CH₂)₃Si(CH₃)(OC_(H) ₅)₂, CH₂═C(CH₃)CO₂(CH₂)₃Si(OC₂H₅)₃,CH₂═C(CH₃)CO₂(CH₂)₃Si(CH₃)(OC₂H₅)₂ and so forth. These compounds may beused singly or two or more of them may be used in admixture.

More preferred are CH₂═CHCO₂(CH₂)₃Si(OCH₃)₃, CH₂═CHCO₂(CH₂)₃Si(CH₃)(OCH₃)₂, CH₂═C(CH₃)CO₂(CH₂)₃Si(OCH₃)₃ andCH₂═C(CH₃)CO₂(CH₂)₃Si(CH₃)(OCH₃)₂.

For preparing a paint composition which can have a high solid contentand can provide excellent elastic properties using the adhesive curablecomposition of the present invention, that vinyl polymer which has atleast one crosslinkable silyl group at a molecular chain terminus ispreferably used. The vinyl polymer may be one produced by copolymerizinga small amount, relative to the vinyl monomer, of a compound having apolymerizable alkenyl group and a crosslinkable silyl group asrepresented by the above general formula (12) with said vinyl monomer tothereby introducing the crosslinkable silyl group into the molecularchain for adjusting the crosslinking site-to-crosslinking site molecularweight.

The mixing ratio in the reaction between said compound having apolymerizable alkenyl group and a crosslinkable silyl group and theother vinyl monomer is not particularly restricted but is preferablysuch that said compound accounts for 1 to 50 mole percent, morepreferably 2 to 40 mole percent, still more preferably 3 to 30 molepercent, based on the total monomer composition to be subjected topolymerization. When the proportion of said compound is less than 1 molepercent, the curability will be insufficient. When it is in excess of 50mole percent, poor storage stability will result.

Since the “controlled radical polymerization method” already describedhereinabove is used here as the polymerization method, the vinyl polymercan be obtained with a narrow molecular weight distribution. Since thepolymer has a viscosity suppressed to a low level owing to the narrowmolecular weight distribution, it is possible to provide the paintcomposition with spreadability, which is required of said composition,with a smaller amount of a solvent.

In addition to the additives mentioned hereinabove as suited forincorporation in the adhesive curable composition, such additives asresins, such as polyester, epoxy and acrylic resins, colorants,spreading agents, antifoams and antistatics may be added to the abovepaint composition, where necessary. The addition amount of suchadditives can judiciously selected according to the characteristics tobe acquired. These additives may be used singly or two or more of themmay be used combinedly.

The colorants mentioned above are not particularly restricted butinclude, among others, inorganic pigments such as titanium dioxide,carbon black, iron oxide and chromium oxide; and organic pigments suchas phthalocyanines and quinacridones.

The above paint composition prepared by adding, according to need, acuring catalyst and additive(s) to the vinyl polymer having at least onecrosslinkable silyl group, then applying the same to substrates andcuring, gives uniform coat films. The hydrolysis and/or condensation ofthe crosslinkable silyl group progresses at room temperature, so that noheating is required in the step of curing. However, heating may be madefor promoting the curing. The heating temperature is 20 to 200° C.,preferably 50 to 180° C.

The paint composition of the present invention may be used as a solventtype one or a water-based type one. It is also possible to use saidcomposition as a powder coating composition by distilled off thevolatile matter from the vinyl polymer, which is the main component, andadding desired ingredients thereto and finely divided the resultingcompound.

BEST MODES FOR CARRYING OUT THE INVENTION

The following examples illustrate the present invention in furtherdetail. It is to be noted, however, that these examples are by no meanslimitative of the scope of the present invention.

REFERENCE EXAMPLE 1

Synthesis of a Hydroxyl-Containing Initiator

In a nitrogen atmosphere, 2-bromopropionyl chloride (2 mL, 3.35 g, 19.5mmol) was slowly added dropwise at 0° C. to a THF solution (10 mL)containing ethylene glycol (10.9 mL, 195 mmol) and pyridine (3 g, 39mmol). The resulting solution was stirred at the same temperature for 2hours. Dilute hydrochloric acid and ethyl acetate were added and mixturewas allowed to separate into two phases. The organic phase was washedwith dilute hydrochloric acid and brine, and dried over Na₂SO₄. Thevolatile matter was distilled off under reduced pressure and a crudeproduct (3.07 g) was obtained. This crude product was distilled underreduced pressure (70-73° C., 0.5 mm Hg) to give hydroxyethyl2-bromopropionate (2.14 g, 56%) represented by the following formula:

H₃CC(H)(Br)C(O)O(CH₂)₂—OH

SYNTHESIS EXAMPLE 1

Synthesis of a Hydroxyl-Terminated Poly(n-butyl Acrylate)

A one-liter pressure reaction vessel was charged with n-butyl acrylate(112 mL, 100 g, 0.78 mol), the hydroxyl-containing initiator obtained inReference Example 1 (3.07 g, 15.6mmol), cuprous bromide(2.24g,15.6mmol), 2,2′-bipyridyl (4.87g, 31.2 mmol), ethyl acetate (80 mL) andacetonitrile (20 mL), the dissolved oxygen was removed by bubbling withnitrogen, and the vessel was sealed. The mixture was heated at 130° C.and the reaction was allowed to proceed for 2 hours. The reaction vesselwas cooled to room temperature, 2-hydroxyethyl methacrylate (3.92 mL,4.06 g, 31.2 mmol) was added, and the reaction was allowed to proceed at110° C. for 2 hours. The mixture was diluted with ethyl acetate (200mL), the insoluble matter was filtered off, the filtrate was washed with10% hydrochloric acid and brine and the organic layer was dried overNa₂SO₄. The solvent was distilled of f under reduced pressure to give 82g of a hydroxyl-terminated poly(n-butyl acrylate). This polymer had aviscosity of 25 Pa·s and a number average molecular weight of 5,100 asdetermined by GPC (mobile phase: chloroform; expressed in terms ofpolystyrene equivalent) with a molecular weight distribution of 1.29.The average number of hydroxyl groups per polymer molecule was 2.4 asdetermined by ¹H-NMR analysis.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

The hydroxyl-terminated poly(n-butyl acrylate) synthesized in the abovemanner (4.94 g, OH 2.30 mmol) was subjected to azeotropic dehydration at50° C. in the presence of toluene. Thereto were added tin octylate (4.9mg) and toluene (6 mL), and methyldimethoxysilylpropyl isocyanate (0.524g, 2.77 mmol) was added dropwise at 50° C. Thereafter, the reactiontemperature was raised to 70° C. and the reaction was further allowed toproceed for 4 hours. Based on the disappearance of a hydroxyl-boundmethylene signal (3.8 ppm) in ¹H-NMR analysis, it was judged that nounreacted hydroxyl groups remained. The volatile matter was distilledoff under reduced pressure to give a crosslinkable silyl-terminatedpoly(n-butyl acrylate). This polymer had a viscosity of 22 Pa·s and anumber average molecular weight of 4,900 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.60.

EXAMPLE 1

The crosslinkable silyl-terminated polymer (100 weight parts)synthesized in Synthesis Example 1 was mixed up with 1 weight parts ofdibutyltin diacetylacetonate, and the mixture was poured into a mold anddeaerated at room temperature using a vacuum drier. After 20 hours ofheating at 50° C. for curing, a uniform rubber-like cured sheet wasobtained. The gel fraction determined by toluene extraction was 93%.

Dumbbell test specimens No. 2(1/3) were punched out from 10 therubber-like cured sheet and subjected to tensile testing (200 mm/min)using an autograph. The breaking strength was 0.31 MPa and the breakingextension was 35%.

SYNTHESIS EXAMPLE 2

Synthesis of an Alkenyl-Terminated Poly(n-butyl Acrylate)

In a nitrogen atmosphere at 75° C., undecenoyl chloride (7.22 mL, 6.81g, 33.6 mmol) was slowly added dropwise to a toluene solution (100 mL)containing the hydroxyl-terminated poly(n-butyl acrylate) (50 g)obtained in Synthesis Example 1 and pyridine (10 mL), and the mixturewas stirred at 75° C. for 3 hours. The white solid formed was filteredoff, and the organic layer was washed with dilute hydrochloric acid andbrine and dried over Na₂SO₄. Concentration under reduced pressure gavean alkenyl-terminated poly(n-butyl acrylate) (43 g). This polymer had anumber average molecular weight of 5,400 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.30. The number of alkenyl groupsintroduced per polymer molecule was 2.3 as determined by ¹H-NMRanalysis.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

A 30-mL pressure reaction vessel was charged with the alkenyl-terminatedpoly(n-butyl acrylate) (2 g) obtained in the above manner,methyldimethoxysilane (0.32 mL), methyl orthoformate (0.09 mL, 3equivalents relative to the alkenyl group) andplatinum(0)-1,1,3,3-tetramethyl-1,3-divinyldisiloxane complex (8.3×10⁻⁸mol/L solution in xylene, 10⁻⁴ equivalents relative to the alkenylgroup), and the mixture was stirred at 100° C. for 1 hour. Removal ofthe volatile matter by distillation under reduced pressure gave 2 g of acrosslinkable silyl-terminated poly(n-butyl acrylate). The polymer had anumber average molecular weight of 5,900 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.37. The number of crosslinkable silylgroups introduced per polymer molecule was 2.2 as determined by ¹H-NMRanalysis.

EXAMPLE 2

The crosslinkable silyl-terminated polymer (1 g) obtained in SynthesisExample 2 was mixed up with a curing catalyst [U-220 (trademark);product of Nitto Kasei; dibutyltin diacetylacetonate; 30 mg], and themixture was poured into a mold, deaerated at room temperature using avacuum drier, and allowed to stand at room temperature for 7 days,whereupon a uniform rubber-like cured product was obtained. The gelfraction was 78%.

EXAMPLE 3

The crosslinkable silyl-terminated polymer (100 weight parts) ofSynthesis Example 2 was mixed up with 1 weight part of water and 1weight part of dibutyltin dimethoxide, and the mixture was poured into amold and deaerated at room temperature using a vacuum drier, followed by20 hours of heating at 50° C. for curing, which gave a uniformrubber-like cured sheet. The gel fraction determined by tolueneextraction was 88%.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.32 MPa and the breaking extensionwas 34%.

SYNTHESIS EXAMPLE 3

Synthesis of a Halogen-Terminated Poly(n-butyl Acrylate)

A 500-mL pressure reaction vessel was charged with n-butyl acrylate (112mL, 100 g, 0.78 mol), dibromoxylene (4.12 g, 15.6 mmol), cuprous bromide(2.24 g, 15.6 mmol), 2,2′-bipyridyl (4.87 g, 31.2 mmol), ethyl acetate(90 mL) and acetonitrile (20 mL), the dissolved oxygen was removed bybubbling with nitrogen, and the vessel was sealed. The mixture washeated to 130° C. and the reaction was allowed to proceed for 2 hours.The reaction vessel was cooled to room temperature, 2-hydroxyethylmethacrylate (3.92 mL, 4.06 g, 31.2 mmol) was added, and the reactionwas allowed to proceed at 110° C. for 2 hours. The mixture was dilutedwith ethyl acetate (200 mL), the insoluble matter was filtered off, 2.24g of cuprous bromide (15.6 mmol), 0.76 g ofpentamethyldiethylenetriamine (4.4 mmol), 5 mL of acetonitrile, 1.6 g ofdiethyl 2,5-dibromoadipate (4.4 mmol) and 44.7 g of butyl acrylate (349mmol) were then added and, after deaeration by freezing, the reactionwas allowed to proceed in a nitrogen atmosphere at 70° C. for 7 hours.Purification by removing the copper catalyst by passing the reactionmixture through an activated alumina column gave a bromine-terminatedpolymer. The polymer obtained had a number average molecular weight of5,700 as determined by GPC (mobile phase: chloroform; expressed in termsof polystyrene equivalent) with a molecular weight distribution of 1.37.

Synthesis of an Alkenyl-Terminated Poly(n-butyl Acrylate)

In a nitrogen atmosphere, a 500-mL flask was charged with 84 g of theabove halogen-terminated poly(n-butyl acrylate), 7.7 g of potassiumpentenoate (56 mmol) and 80 mL of DMAc and the reaction was allowed toproceed at 70° C. for 4 hours. The unreacted portion of potassiumpentenoate and the byproduct potassium bromide were removed from thereaction mixture by extractive purification with water, to give analkenyl-terminated polymer. This polymer (70 g) and an equal amount ofaluminum silicate [Kyowaad 700 PEL (trademark); product of KyowaChemical] were mixed together in toluene, and the mixture was stirred at100° C. Four hours later, the aluminum silicate was filtered off, andthe polymer was purified by distilling off the volatile matter byheating under reduced pressure. The polymer obtained had a numberaverage molecular weight of 4,760 as determined by GPC (mobile phase:chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.73. The number of alkenyl groups perpolymer molecule as determined by ¹H-NMR was 1.78.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

A 200-mL pressure reaction vessel was charged with thealkenyl-terminated polymer (60 g) obtained in the above manner, 8.4 mLof methyldimethoxysilane (68.1 mmol), 2.5 mL of methyl orthoformate(22.9 mmol) and 5×10⁻³ mmol ofplatinum-bis(divinyltetramethyldisiloxane), and the reaction was allowedto proceed at 100° C. for 4 hours, to give a crosslinkablesilyl-terminated polymer. The polymer obtained had a number averagemolecular weight of 6,010 as determined by GPC (mobile phase:chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.44. The number of crosslinkable silylgroups per polymer molecule as determined by ¹H-NMR was 1.59.

EXAMPLE 4

The crosslinkable silyl-terminated polymer (100 weight parts) obtainedin Synthesis Example 3 was mixed up with 1 weight part of water and 1weight part of dibutyltin dimethoxide with stirring, and the mixture waspoured into a 2-mm-thick mold. Deaeration at room temperature using avacuum drier, followed by 2 days of heating at 50° C. for curing, gave auniform rubber-like cured sheet. The gel fraction determined by tolueneextraction was 93%.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.26 MPa and the breaking extensionwas 75%.

SYNTHESIS EXAMPLE 4

Synthesis of a Halogen-Terminated Poly(n-butyl Acrylate)

A 50-mL flask was charged with 0.63 g of cuprous bromide (4.4 mmol),0.76 g of pentamethyldiethylenetriamine (4.4 mmol), 5 mL ofacetonitrile, 1.6 g of diethyl 2,5-dibromoadipate (4.4 mmol) and 44.7 gof butyl acrylate (349 mmol) and, after deaeration by freezing, thereaction was allowed to proceed in a nitrogen atmosphere at 70° C. for 7hours. The reaction mixture was passed through an activated aluminacolumn for removing the copper catalyst for purification, to give abromine-terminated polymer. The polymer obtained had a number averagemolecular weight of 10,700 as determined by GPC (mobile phase:chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.15.

Synthesis of an Alkenyl-Terminated Poly(n-butyl Acrylate)

In a nitrogen atmosphere, a 200-mL flask was charged with 35 g of thehalogen-terminated poly(n-butyl acrylate) obtained in the above manner,2.2 g of potassium pentenoate (16.1 mmol) and DMAc (35 mL), and thereaction was allowed to proceed at 70° C. for 4 hours. The unreactionportion of potassium pentenoate and the byproduct potassium bromide wereremoved from the reaction mixture by extractive purification with water,to give an alkenyl-terminated polymer. The polymer obtained had a numberaverage molecular weight of 11,300 as determined by GPC (mobile phase:chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.12. The number of alkenyl groups perpolymer molecule as determined by ¹H-NMR was 1.82.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

A 200-mL pressure reaction vessel was charged with 15 g of thealkenyl-terminated polymer obtained in the above manner, 1.8 mL ofmethyldimethoxysilane (14.5 mmol), 0.26 mL of methyl orthoformate (2.4mmol) and platinum-bis(divinyltetramethyldisiloxane) (10⁻⁴ mmol), andthe reaction was allowed to proceed at 100° C. for 4 hours, to give acrosslinkable silyl-terminated polymer. The polymer obtained had aviscosity of 44 Pa·s and a number average molecular weight of 11,900 asdetermined by GPC (mobile phase: chloroform; expressed in terms ofpolystyrene equivalent) with a molecular weight distribution of 1.12.The number of crosslinkable silyl groups per polymer molecule asdetermined by ¹H-NMR was 1.46.

EXAMPLE 5

The crosslinkable silyl-terminated polymer obtained in Synthesis Example4 (100 weight parts) was mixed up with 1 weight part of water and 1weight part of dibutyltin dimethoxide with stirring and the mixture waspoured into a 2-mm-thick mold. Deaeration at room temperature using avacuum drier, followed by 10 days of heating at 50° C. for curing, gavea uniform rubber-like cured sheet. The gel fraction determined bytoluene extraction was 98%.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.35 MPa and the breaking extensionwas 77%.

SYNTHESIS EXAMPLE 5

Synthesis of an Alkenyl-Terminated Poly(n-butyl Acrylate)

A 100-mL glass reaction vessel was charged with butyl acrylate (50.0 mL,44.7 g, 0.349 mol), cuprous bromide (1.25 g, 8.72 mmol),pentamethyldiethylenetriamine (1.82 mL, 1.51 g, 8.72 mmol) andacetonitrile (5 mL) and, after cooling and deaeration under vacuum, thevessel was purged with nitrogen gas. After thorough stirring, diethyl2,5-dibromoadipate (1.57 g, 4.36 mmol) was added, and the mixture wasstirred at 70° C. After 60 minutes of stirring, 1,7-octadiene (6.44 mL,4.80 g, 43.6 mmol) was added, and heating was continued at 70° C. withstirring for 2 hours. The mixture was treated with activated alumina andthe volatile matter was then distilled off under reduced pressure. Theremaining product was dissolved in ethyl acetate and the solution waswashed with 2% hydrochloric acid and brine. The organic layer was driedover Na₂SO₄ and the volatile matter was distilled off by heating underreduced pressure to give an alkenyl-terminated polymer. The polymerobtained had a number average molecular weight of 13,100 (expressed interms of polystyrene equivalent) as determined by GPC, with a molecularweight distribution of 1.22. The degree of olefinic functional groupintroduction on the number average molecular weight basis was 2.01.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

The alkenyl-terminated poly(n-butyl acrylate) (30.5 g) obtained in theabove manner was blended with an equal amount of aluminum silicate[Kyowaad 700 PEL (trademark); product of Kyowa Chemical] in toluene, andthe mixture was stirred at 100° C. Four hours later, the aluminumsilicate was filtered off and the polymer was purified by distilling offthe volatile matter from the filtrate by heating under reduced pressure.

A 200-mL glass-made pressure reaction vessel was charged with the abovepurified polymer (23.3 g), dimethoxymethylsilane (2.55 mL, 20.7 mmol),dimethyl orthoformate (0.38 mL, 3.45 mmol) and the platinum catalyst.The platinum catalyst was used in a mole ratio of 2×10⁻⁴ equivalentsrelative to the alkenyl group in the polymer. The reaction mixture washeated at 100° C. for 3 hours. The volatile matter was distilled offunder reduced pressure from the mixture to give a crosslinkablesilyl-terminated poly(n-butyl acrylate). The polymer obtained had anumber average molecular weight of 13,900 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.25. The number of crosslinkable silylgroups per polymer molecule as determined by ¹H-NMR was 1.58.

EXAMPLE 6

The crosslinkable silyl-terminated polymer (100 weight parts) obtainedin Synthesis Example 5 was blended with 1 weight part of water and 1weight part of dibutyltin dimethoxide with stirring, and the mixture waspoured into a 2-mm-thick mold. Deaeration at room temperature using avacuum drier and the subsequent 10 days of heating at 50° C. for curinggave a uniform rubber-like cured sheet. The gel fraction determined bytoluene extraction was 85%.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.34 MPa and the breaking extensionwas 86%.

SYNTHESIS EXAMPLE 6

Synthesis of a Halogen-Terminated Poly(n-butyl Acrylate)

A 50-mL flask was charged with 0.63 g of cuprous bromide (4.4 mmol),0.76 g of pentamethyldiethylenetriamine (4.4 mmol), 5 mL ofacetonitrile, 0.78 g of diethyl 2,5-dibromoadipate (2.2 mmol) and 44.7 gof butyl acrylate (349 mmol) and, after deaeration by freezing, thereaction was allowed to proceed in a nitrogen atmosphere at 70° C. for 6hours. Purification by passing the reaction mixture through an activatedalumina column to remove the copper catalyst gave a bromine-terminatedpolymer. The polymer obtained had a number average molecular weight of23,600 as determined by GPC (mobile phase: chloroform; expressed interms of polystyrene equivalent) with a molecular weight distribution of1.14.

Synthesis of an Alkenyl-Terminated Poly(n-butyl Acrylate)

In a nitrogen atmosphere, a 200-mL flask was charged with 34 g of thehalogen-terminated poly(n-butyl acrylate) obtained in Synthesis Example6, 1.0 g of potassium pentenoate (7.6 mmol) and 34 mL of DMAc, and thereaction was allowed to proceed at 70° C. for 4 hours. The unreactedportion of potassium pentenoate and the byproduct potassium bromide wereremoved from the reaction mixture by extractive purification with water,to give an alkenyl-terminated polymer. This alkenyl-terminated polymerand an equal amount (30.5 g) of aluminum silicate [Kyowaad 700 PEL(trademark); product of Kyowa Chemical] were mixed together in toluene,and the mixture was stirred at 100° C. Four hours later, the aluminumsilicate was filtered off and the polymer was purified by distilling offthe volatile matter from the filtrate by heating under reduced pressure.The polymer obtained had a number average molecular weight of 24,800 asdetermined by GPC (mobile phase: chloroform; expressed in terms ofpolystyrene equivalent) with a molecular weight distribution of 1.14.The number of alkenyl groups per polymer molecule was 1.46 as determinedby ¹H-NMR.

Synthesis of a Crosslinkable Silyl-Terminated Poly(n-butyl Acrylate)

A 200-mL pressure reaction tube was charged with 21 g of thealkenyl-terminated polymer obtained in the above manner, 0.94 mL ofmethyldimethoxysilane (7.6 mmol), 0.13 mL of methyl orthoformate (1.3mmol) and 2×10⁻⁴ mmol of platinum-bis(divinyltetramethyldisiloxane, andthe reaction was allowed to proceed at 100° C. for 4 hours, to give acrosslinkable silyl-terminated polymer. The polymer obtained had aviscosity of 100 Pa·s and a number average molecular weight of 25,400 asdetermined by GPC (mobile phase: chloroform; expressed in terms ofpolystyrene equivalent) with a molecular weight distribution of 1.16.The number of crosslinkable silyl groups per polymer molecule was 1.48as determined by ¹H-NMR.

EXAMPLE 7

The crosslinkable silyl-terminated polymer (100 weight parts) obtainedin Synthesis Example 6 was blended with 1 weight part of water and 1weight part of dibutyltin dimethoxide with stirring, and the mixture waspoured into a 2-mm-thick mold. Deaeration at room temperature using avacuum drier and the subsequent 2 days of heating at 50° C. for curinggave a uniform rubber-like cured sheet. The gel fraction was 94% asdetermined by toluene extraction.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.40 MPa and the breaking extensionwas 323%.

COMPARATIVE SYNTHESIS EXAMPLE 1

Synthesis of a Hydroxyl-Terminated Poly(n-butyl Acrylate) Using aHydroxyl-Containing Disulfide

According to Example 1 of Japanese Kokai Publication Hei-5-262808, a100-mL flask was charged with 2-hydroxyethyl disulfide (30.8 g, 0.2mol). The flask was heated to 100° C., and a mixture of n-butyl acrylate(12.8 g, 0.1 mol) and AIBN (0.328 g, 0.002 mol) were added dropwise over30 minutes. The mixture was further stirred at 100° C. for 1 hour.Toluene (20 mL) was added, the mixture was allowed to stand in aseparating funnel, and the lower layer was separated. The upper layerwas washed with three portions of water and dried over Na₂SO₄, and thevolatile matter was distilled off under reduced pressure, to give ahydroxyl-terminated poly(n-butyl acrylate) (12.2 g, 95%). This polymerhad a viscosity of 49 Pa·s and a number average molecular weight of4,200 as determined by GPC (mobile phase: chloroform, expressed in termsof polystyrene equivalent) with a molecular weight distribution of 4.16.

Synthesis of a Crosslinkable Silyl-Containing Poly(n-butyl Acrylate)Using a Hydroxyl-Containing Disulfide

The hydroxyl-terminated poly(n-butyl acrylate) (4.52 g, OH=1.85 mmol)synthesized in the above manner was subjected to azeotropic dehydrationat 50° C. in the presence of toluene. Thereto were added tin octylate(4.52 mg) and toluene (6 mL), and methyldimethoxysilylpropyl isocyanate(0.421 g, 2.22 mmol) was added dropwise at 50° C. Thereafter, thereaction temperature was raised to 70° C. and the reaction was allowedto proceed continuedly for 4 hours. Based on the disappearance of ahydroxyl-bound methylene signal (3.8 ppm) in ¹H-NMR, it was judged thatno unreacted hydroxyl group remained. The volatile matter was distilledoff under reduced pressure to give a crosslinkable silyl-terminatedpoly(n-butyl acrylate). This polymer had a viscosity of 53 Pa·s and anumber average molecular weight of 4,700 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 3.71.

COMPARATIVE EXAMPLE 1

The crosslinkable silyl-terminated polymer (100 weight parts) ofComparative Example 1 was mixed up with 1 weight part of dibutyltindiacetylacetonate, and the mixture was poured into a mold and deaeratedat room temperature using a vacuum drier. Heating at 50° C. for 20 hoursfor curing gave a uniform rubber-like cured sheet. The gel fractiondetermined by toluene extraction was 82%. The extract fraction wasconcentrated and the concentrate was subjected to ¹H-NMR; nocrosslinkable silyl group was found therein.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.21 MPa and the breaking extensionwas 93%.

COMPARATIVE SYNTHESIS EXAMPLE 2

Synthesis of a Crosslinkable Silyl-Containing Poly(n-butyl Acrylate)Using a Crosslinkable Silyl-Containing Monomer

In a one-liter flask, 385 g of butyl acrylate and 15 g ofmethyldimethoxysilylpropyl methacrylate were polymerized in 400 g oftoluene in the presence of 6 g of azobisisobutyronitrile at 105° C. for7 hours with bubbling with nitrogen. Then, the toluene was distilled offto give a crosslinkable silyl-containing poly(n-butyl acrylate). Thispolymer had a viscosity of 74 Pa·s and a number average molecular weightof 8,500 as determined by GPC (mobile phase: chloroform; expressed interms of polystyrene equivalent) with a molecular weight distribution of2.47. The average number of hydroxyl groups per polymer molecule was1.40 as determined by ¹H-NMR analysis.

COMPARATIVE EXAMPLE 2

The crosslinkable silyl-containing polymer (100 weight parts) ofComparative Synthesis Example 2 was blended with 1 weight part of waterand 1 weight part of dibutyltin dimethoxide with stirring, and themixture was poured into a 2-mm-thick mold and deaerated at roomtemperature using a vacuum drier. Upon heating at 50° C. for 10 days forcuring, a uniform rubber-like cured sheet was obtained. The gel fractionwas 78% as determined by toluene extraction.

Dumbbell test specimens No. 2(1/3) were punched out from the rubber-likecured sheet and subjected to tensile testing (200 mm/min) using anautograph. The breaking strength was 0.14 MPa and the breaking extensionwas 69%.

COMPARATIVE SYNTHESIS EXAMPLE 3

Synthesis of a Crosslinkable Silyl-Containing Poly(n-butyl Acrylate)Using a Crosslinkable Silyl-Containing Monomer

In a one-liter flask, 293 g of butyl acrylate and 7.2 g ofmethyldimethoxysilylpropyl methacrylate were polymerized in 210 g oftoluene in the presence of 1.8 g of azobisisovaleronitrile at 105° C.for 7 hours with bubbling with nitrogen. Then, the toluene was distilledoff to give a crosslinkable silyl-containing poly(n-butyl acrylate).This polymer had a viscosity of 110 Pa·s and a number average molecularweight of 9,600 as determined by GPC (mobile phase: chloroform;expressed in terms of polystyrene equivalent) with a molecular weightdistribution of 2.86.

The results obtained in Examples 1 to 7 except for Example 2 and ofComparative Examples 1 and 2 and Comparative Synthesis Example 3 areshown below in Table 1.

TABLE 1 Ex. 1 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Compar. Ex. 1 Compar. Ex. 2— Polymer Synthesis Synthesis Synthesis Synthesis Synthesis SynthesisCompar. Compar. Compar. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 SynthesisEx. 1 Synthesis Ex. 2 Synthesis Ex. 3 Viscosity (Pa*s) 22 — — 44 — 10053 74 110 Mn 4900 5900 6900 11900 13900 25400 4700 8500 9600 Mw/Mn 1.601.37 1.44 1.12 1.25 1.16 3.71 2.47 2.86 Fn 2.39 2.24 1.59 1.46 1.58 1.481.42 1.40 — Gel fraction (%) 93 88 93 98 85 94 82 78 — Breaking strength(Mpa) 0.31 0.32 0.26 0.35 0.34 0.40 0.21 0.14 — Breaking extention (%)35 34 75 77 86 323 93 69 — Fn: Average number of crosslinking silylgroups per molecule.

The crosslinkable silyl-containing vinyl polymers of the presentinvention have a narrow molecular weight distribution, hence have a verylow viscosity as compared with the polymers of the comparative synthesisexamples which are roughly comparable in molecular weight, and aresuperior in handling properties (for example, the viscosity of theproduct of Synthesis Example 1 is not more than half of that of theproduct of Comparative Synthesis Example 1; the same is true for thecomparison between Synthesis Example 4 and Comparative Synthesis Example3). When the viscosity the polymer should have is roughly specified, thepolymer can be synthesized so as to have a higher molecular weight,hence can provide cured products having a better balance betweenstrength and elongation (as seen, for example, in Synthesis Example 6).Furthermore, since the crosslinkable silyl-containing vinyl polymer issynthesized by living radical polymerization, the amount of polymermolecules containing no crosslinkable silyl group in said polymer issmaller even when the content of the crosslinkable silyl group permolecule is roughly identical to that in prior art polymers; as aresult, cured products higher in gel fraction can be obtained (Example 5versus Comparative Example 1).

EXAMPLE 8

Heat Resistance of a Cured Product

A portion of the cured sheet obtained in Example 5 was placed in an ovenmaintained at 150° C. and, after the lapse of 24 hours, it was taken outand the surface condition was observed. No abnormality was found in thesurface condition.

COMPARATIVE SYNTHESIS EXAMPLE 4

Synthesis of a Crosslinkable Silyl-Terminated Polydimethylsiloxane(Silicone)

A 200-mL flask was charged with 97 g of a vinyl-terminatedpolydimethylsiloxane [mol. wt. 17,200; DMS-V25 (trademark); product ofAzumax; unsaturated group equivalent: 0.11 eq/kg], 2.3 g ofmethyldimethoxysilane (21.4 mmol) and 10⁻³ mmol ofplatinum-bis(divinyltetramethyldisiloxane), and the reaction was allowedto proceed at 70° C. for 6 hours. The thus-obtained, crosslinkablesilyl-terminated polydimethylsiloxane had a number average molecularweight of 11,900 as determined by GPC (mobile phase: chloroform;expressed in terms of polystyrene equivalent) with a molecular weightdistribution of 2.52. It was found by ¹H-NMR that the unsaturatedgroup-due peak had disappeared. The number of crosslinkable silyl groupsper polydimethylsiloxane molecule was 2 as determined from the intensityratio between the polymer chain silicon-bound methyl protons and themethoxysilyl protons. The viscosity was 6 poises.

COMPARATIVE EXAMPLE 3

Heat Resistance of a Cured Product

The crosslinkable silyl-containing polymer (100 weight parts) ofComparative Synthesis Example 4 was mixed up with 1 weight part of waterand 1 weight part of dibutyltin dimethoxide with stirring, and themixture was poured into a 2-mm-thick mold. After deaeration underreduced pressure, curing was effected by heating at 50° C. for 10 days.A portion of the cured sheet obtained was placed in an oven maintainedat 150° C. and, after the lapse of 24 hours, it was taken out and thesurface condition was checked. No abnormality was found on the surface.

COMPARATIVE SYNTHESIS EXAMPLE 5

Synthesis of Allyl-Terminated Polyisobutylene

A two-liter glass-made pressure polymerization vessel was purged withnitrogen and charged with 205 mL of molecular sieve-driedethylcyclohexane, 819 mL of toluene and 2.89 g of p-dicumylchloride(12.5 mmol). Monomericisobutylene (332 mL, 3.91 mol) was introduced intothe polymerization vessel and, then, 0.454 g of 2-methylpyridine (4.88mmol) and 6.69 mL of titanium tetrachloride (61.0 mmol) were added tothereby initiate the polymerization. After the lapse of a reactionperiod of 70 minutes, 6.86 g of allyltrimethylsilane (60.0 mmol) wasadded for allyl group introducing into polymer termini. After the lapseof a reaction period of 120 minutes, the reaction mixture was washedwith water and the solvent was distilled off to give allyl-terminatedpolyisobutylene.

Synthesis of a Crosslinkable Silyl-Terminated Polyisobutylene

The allyl-terminated polymer (200 g) obtained in the above manner washeated to about 75° C. and, then, methyldimethoxysilane (1.5 eq/vinylgroup) and platinum-(vinylsiloxane) complex (5×10⁻⁵ eq/vinyl group) andthe hydrosilylation reaction was allowed to proceed. The reaction wasfollowed by FT-IR. The absorption of olefin at 1640 cm⁻¹ disappeared inabout 20 hours.

The thus-obtained polyisobutylene polymer had a viscosity of 360 Pa·sand a number average molecular weight of 4,800 as determined by GPC(mobile phase: chloroform; expressed in terms of polystyrene equivalent)with a molecular weight distribution of 1.52. The number ofcrosslinkable silyl groups per polymer molecule was 1.66 as determinedby ¹H-NMR analysis.

COMPARATIVE EXAMPLE 4 Heat Resistance of a Cured Product

The crosslinkable silyl-containing polymer (100 weight parts) ofComparative Synthesis Example 5 was mixed up with 1 weight part of waterand 1 weight part of dibutyltin dimethoxide with stirring, and themixture was poured into a 2-mm-thick mold. After deaeration underreduced pressure, curing was effected by heating at 50° C. for 10 days.A portion of the cured product obtained was placed in an oven maintainedat 150° C. and, after 24 hours, it was taken out and the surfacecondition was observed. The surface was found molten, with partialexudation.

The results obtained in Example 8 and Comparative Examples 3 and 4 areshown in Table 2.

TABLE 2 Example 8 Compar. Ex. 3 Compar. Ex. 4 Polymer Poly(n-butylPolydimethyl- Polyisobutylene acrylate) siloxane Heat resist- Noabnormality No abnormality Surface ance of cured melting product

The cured product from the crosslinkable silyl-containing vinyl polymerhas the same level of heat resistance as that of silicone polymers andis superior in heat resistance to polyisobutylenes and, therefore, canbe used in those fields in which heat resistance is required.

EXAMPLE 9 Accelerated Weathering Resistance

A portion of the cured product obtained in Example 5 was subjected toaccelerated weathering resistance testing using a sunshineweather-o-meter, followed by surface condition observation. Even afterthe lapse of 1,000 hours, neither surface melting nor discoloration wasobserved.

COMPARATIVE EXAMPLES 5 AND 6 Accelerated Weathering Resistance

An accelerated weathering resistance test was performed in the samemanner as in Example 9 except that, in Comparative Example 5, thesilicone polymer obtained in Comparative Synthesis Example 4 was used inlieu of the cured sheet obtained in Example 5 and, in ComparativeExample 6, the polyisobutylene polymer obtained in Comparative SynthesisExample 5 was used. In Comparative Example 5, even after the lapse of1,000 hours, no surface melting or discoloration was observed. On theother hand, surface melting had begun after the lapse of 500 hours.

The crosslinkable silyl-containing vinyl polymer of the presentinvention has the same level of weathering resistance as that ofsilicone polymers and by far superior in weathering resistance to thepolyisobutylene type polymers, so that it can be used in those fields inwhich weathering resistance is required.

EXAMPLE 10 One-Component Core Curability

The crosslinkable silyl-containing polymer (100 weight parts) obtainedin Synthesis Example 5 was subjected to azeotropic dehydration usingtoluene. In a nitrogen atmosphere, 1 weight part ofmethyltrimethoxysilane and 1 weight part of dibutyltin diacetylacetonatewere added in that order, and the mixture was stored in a tightly closedsample bottle as a one-component formulation. After one week of storagein a constant-temperature, constant-humidity room (23° C., 60% RH), themixture was discharged into a sample tube. After 24 hours followingdischarge, the cured portion was taken out and the thickness thereof inthe direction of depth was measured and found to be 3 mm.

COMPARATIVE EXAMPLES 7 AND 8 One-Component Core Curability

Core curability measurements were performed in the same manner as inExample 9 except that, in Comparative Example 7, the silicone polymerobtained in Comparative Synthesis Example 4 was used in lieu of thepolymer obtained in Synthesis Example 5 and, in Comparative Example 8,the polyisobutylene polymer obtained in Comparative Synthesis Example 5was used. In Comparative Example 7, the core curability was 3 mm. InComparative Example 8, only a thin film was found on the surface and nocuring was detected in the core.

The composition comprising the crosslinkable silyl-containing vinylpolymer of the present invention has the same level of one-componentcore curability as that of the silicone-based composition and is by farsuperior in one-component core curability to the polyisobutylene-basedcomposition and, therefore, can be used as a one-component sealingcomposition.

EXAMPLES 11 Adhesiveness

To 100 weight parts of the crosslinkable silyl-containing poly(n-butylacrylate) obtained in Synthesis Example 5 were added 120 weight parts ofcolloidal calcium carbonate, 50 weight parts of dioctyl phthalate, 2weight parts of an amino-containing crosslinkable silyl-containingcompound, A-1120 (trademark; product of Nippon Unicar) and 1 weight partof dibutyltin diacetylacetonate and, after thorough mixing, the mixturewas processed into a bead form on a glass substrate. After 7 days ofstanding at room temperature, the adhesiveness was evaluated by makingan interfacial incision and peeling off the beads. The brakage was foundto be a cohesive failure of the cured composition.

The crosslinkable silyl-containing vinyl polymer of the presentinvention has a sufficient level of adhesiveness and can satisfactorilyused as an adhesive curable composition.

EXAMPLE 12 Coatability

To 100 weight parts of the crosslinkable silyl-containing poly(n-butylacrylate) obtained in Synthesis Example 5 were added 10 weight parts oftitanium oxide, 100 weight parts of colloidal calcium carbonate, 40weight parts of heavy calcium carbonate and the reaction product from 3weight parts of tin octylate and 0.75 weight part of laurylamine. Afterthorough mixing, the mixture was processed into a sheet. On the next dayfollowing sheet making, an acrylic emulsion paint (Water-base Top,product of Nippon Paint) diluted with 10% of water was applied. Coatingcould be performed without problem.

COMPARATIVE EXAMPLE 9 Coatability

The same experiment as in Example 12 was made using the crosslinkablesilyl-containing polydimethylsiloxane obtained in Comparative SynthesisExample 4 in lieu of the crosslinkable silyl-containing poly(n-butylacrylate) obtained in Synthesis Example 5. Upon Application, the paintwas immediately repelled.

Unlike the composition based on the silicone polymer, the compositioncomprising the crosslinkable silyl-containing vinyl polymer of thepresent invention had sufficient coatability. Therefore, the compositionof the present invention can be used as a curable composition forproviding a coatable sealing material.

EXAMPLE 13 Stain Resistance

To 100 weight parts of the crosslinkable silyl-containing poly(n-butylacrylate) obtained in Synthesis Example 5 were added 10 weight parts oftitanium oxide, 100 weight parts of colloidal calcium carbonate, 40weight parts of heavy calcium carbonate and the reaction product from 3weight parts of tin octylate and 0.75 weight part of laurylamine. Afterthorough mixing, the mixture was filled into the joint between granitepieces coated with a primer (No.40, product of Yokohama Rubber),followed by outdoor exposure. Even after the lapse of 8 months, thevicinity of the joint was clean.

COMPARATIVE EXAMPLE 10 Stain Resistance

The same experiment as in Example 13 was made using the crosslinkablesilyl-containing polydimethylsiloxane obtained in Comparative SynthesisExample 4 in lieu of the crosslinkable silyl-containing poly(n-butylacrylate) obtained in Synthesis Example 4. After the lapse of 8 months,the vicinity of the joint was stained gray.

Unlike the composition based on the silicone polymer, the compositioncomprising the crosslinkable silyl-containing vinyl polymer of thepresent invention did not stain the granite pieces. Therefore, it can beused as a nonstaining sealing material or a like curable composition.

EXAMPLE 14 Adhesive Composition

The crosslinkable silyl-containing poly(n-butyl acrylate) (100 weightparts) obtained according to the same formulation as employed inSynthesis Example 4 was mixed up with 175 weight parts of a 40% toluenesolution of a special rosin ester [Super Ester A-100 (trademark);product of Arakawa Chemical Industries] and 2 weight parts of a tincatalyst [#918 (trademark; product of Sankyo Organic] and the mixturewas applied to a PET film using a 100-m coater. After one day ofstanding at room temperature, the coating was heated at 50° C. for aday. According to JIS Z 0237, test specimens were prepared for a 180°peeling test and the adhesion was tested and found to be 4.5 N/25 mm.

From this result, it is seen that the crosslinkable silyl-containingvinyl polymer of the present invention can be used as an adhesive agent.

SYNTHESIS EXAMPLE 8 Synthesis of a Crosslinkable Silyl-Containingn-butyl Acrylate-Methyl Methacrylate Copolymer

A 200-mL flask was charged with 1.4 g of cuprous bromide (9.8 mmol), 1.2g pentamethyldiethylenetriamine (6.7 mmol), acetonitrile (20 mL), butylacetate (80 mL), 4.4 g of diethyl 2,5-dibromoadipate (12.2 mmol), 25.0 gof butyl acrylate (195 mmol), 68.4 g of methyl methacrylate (684 mmol)and 5.7 g of methyldimethoxysilylpropyl methacrylate (24.4 mmol). Afterdeaeration by freezing, the reaction was allowed to proceed in anitrogen atmosphere at 70° C. for 7 hours. The reaction mixture waspassed through an activated alumina column to thereby remove the coppercatalyst for purification, to give a crosslinkable silyl-containingn-butyl acrylate/methyl methacrylate copolymer. The polymer obtained hada number average molecular weight of 12,500 as determined by GPC (mobilephase: chloroform; expressed in terms of polystyrene equivalent) with amolecular weight distribution of 1.55. The viscosity of a 65% toluenesolution of the copolymer obtained was 10 Pa·s.

EXAMPLE 15

To 100 weight parts (as solids) of the copolymer obtained in SynthesisExample 8 was added 1 weight part of a tin-based curing catalyst [#918(trademark); product of Sankyo Organic], and the mixture was applied toa steel sheet and a teflon sheet using a 150-μm coater. The coatingformed on the steel sheet was allowed to stand at room temperature for 2days and then the 60° mirror reflectance was measured and found to be96. The coating formed on the teflon sheet was matured at roomtemperature for 1 day and then at 50° C. for 3 days. The coating piecewas placed on a wire gauze and immersed in toluene for 1 day and thendried at 80° C. under reduced pressure for 4 hours. The thus-determinedgel fraction was 86%.

COMPARATIVE SYNTHESIS EXAMPLE 6 Synthesis of a CrosslinkableSilyl-Containing n-butyl Acrylate-Methyl Methacrylate Copolymer

A mixture of toluene (800 g), butyl acrylate (208 g), methylmethacrylate (552 g), methyldimethoxysilylpropyl methacrylate (40 g) andazobisisobutyronitrile (24 g) in a two-liter flask was subjected topolymerization at 105° C. for 7 hours while bubbling with nitrogen. Thethus-obtained, crosslinkable silyl-containing n-butyl acrylate/methylmethacrylate copolymer has a number average molecular weight of 7,400 asdetermined by GPC (mobile phase: chloroform; expressed in terms ofpolystyrene equivalent) with a molecular weight distribution of 1.87. A69% toluene solution of the copolymer obtained had a viscosity of 10Pa·s.

COMPARATIVE EXAMPLE 11

In the same manner as in Example 15, 1 weight part of a tin-based curingcatalyst [#918 (trademark); product of Sankyo Organic] was added to 100weight parts (as solids) of the copolymer obtained in ComparativeSynthesis Example 6 and the mixture was applied to a steel sheet and ateflon sheet using a 150-m coater. The coating formed on the steel sheetwas allowed to stand at room temperature for 2 days and then the 600mirror reflectance was measured and found to be 96. The coating formedon the teflon sheet was matured at room temperature for 1 day and thenat 50° C. for 3 days. The coating piece was placed on a wire gauze andimmersed in toluene for 1 day and then dried at 80° C. under reducedpressure for 4 hours. The thus-determined gel fraction was 71%.

The crosslinkable silyl-containing vinyl polymer of the presentinvention has a narrow molecular weight, so that even when it has a highmolecular weight, the viscosity increase is slight and a high solidcontent composition can be prepared. At the same time, a paintcomposition giving a high gel fraction and a high level of gloss can beobtained.

INDUSTRIAL APPLICABILITY

The composition of the present invention is excellent in weatheringresistance and heat resistance and low in viscosity. Therefore, it canbe used in a sealing composition which is easy to handle and capable ofbeing packed as a one-component formulation and has good coatability.Because of its good weathering resistance and heat resistance and lowviscosity, it can also be used in a paint composition or pressuresensitive adhesive composition which has a high solid content and isless unfriendly to the environment.

What is claimed is:
 1. A method for reducing viscosity of an adhesivecurable composition comprising a vinyl polymer having at least onecrosslinkable silyl group represented by the general formula (1):—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)_(a)  (1) wherein each R¹ andR² represents an alkyl group containing 1 to 20 carbon atoms, an arylgroup containing 6 to 20 carbon atoms, an aralkyl group containing 7 to20 carbon atoms or a triorganosiloxy group represented by the formula(R′)₃SiO— wherein R′ represents a monovalent hydrocarbon groupcontaining 1 to 20 carbon atoms and the plural R′ groups may be the sameor different and, when there are two or more R¹ or R² groups, they maybe the same or different; Y represents a hydroxyl group or ahydrolyzable group and, when there are two or more Y groups, they may bethe same or different; a represents 0, 1, 2 or 3; b represents 0, 1 or2; and m represents an integer of 0 to 19; with the condition that a, band m satisfy the relation a+mb≧1, comprising adjusting a weight averagemolecular weight-to-number average molecular weight ratio of said vinylpolymer to less than 1.8 as determined by permeation chromatography. 2.A method for reducing a solvent content in an adhesive curablecomposition comprising a solvent and a vinyl polymer having at least onecrosslinkable silyl group represented by the general formula (1) ascompared to a solvent content of a composition having the same viscosityand comprising a solvent and a polymer having a molecular weightdistribution of at least 1.8:—[Si(R¹)_(2-b)(Y)_(b)O]_(m)—Si(R²)_(3-a)(Y)^(a)  (1) wherein each R¹ andR² represents an alkyl group containing 1 to 20 carbon atoms, an arylgroup containing 6 to 20 carbon atoms, an aralkyl group containing 7 to20 carbon atoms or a triorganosiloxy group represented by the formula(R′)₃SiO— wherein R′ represents a monovalent hydrocarbon groupcontaining to 1 to 20 carbon atoms and the plural R′ groups may be thesame or different and, when there are two or more R¹ or R² groups, theymay be the same or different; Y represents a hydroxyl group or ahydrolyzable group and, when there are two or more Y groups, they may bethe same or different; a represents 0, 1, 2 or 3; b represents 0, 1 or2; and m represents an integer of 0 to 19; with the condition that a, band m satisfy the relation a+mb≧1, comprising adjusting a weight averagemolecular weight-to-number average molecular weight ratio of said vinylpolymer to less than 1.8 as determined by gel permeation chromatography.3. The method according to claim 1, wherein the adhesive curablecomposition comprises 0.01 to 20 parts by weight of an adhesionpromoter, relative to 100 parts by weight of said vinyl polymer.
 4. Themethod according to claim 1, wherein the vinyl polymer is a(meth)acrylic polymer.
 5. The method according to claim 1, wherein thevinyl polymer is produced by living radical polymerization.
 6. Themethod according to claim 1, wherein the vinyl polymer is produced byatom transfer radical polymerization.
 7. The method according to claim1, wherein said vinyl polymer has at least one crosslinkable silyl grouprepresented by the general formula (1) at a molecular chain terminus. 8.The method according to claim 1, wherein the vinyl polymer having atleast one crosslinkable silyl group represented by the general formula(1) is produced by the steps of: (1) subjecting a vinyl monomer toradical polymerization using an organic halide or halogenated sulfonylcompound as the initiator and a transition metal complex as the catalystto produce a halogen-terminated vinyl polymer; (2) reacting saidhalogen-terminated vinyl polymer with an alkenyl-terminated vinylpolymer; and (3) reacting said alkenyl-terminated vinyl polymer with ahydrosilane compound having a crosslinkable silyl group represented bythe general formula (1).
 9. The method according to claim 1, wherein thevinyl polymer having at least one crosslinkable silyl group representedby the general formula (1) is produced by the steps of: (1) subjecting avinyl monomer to living radical polymerization to produce a vinylpolymer; and (2) consecutively reacting said vinyl polymer of step (1)with a compound having at least two low-polymerizable alkenyl groups toproduce an alkenyl-terminated vinyl polymer and reacting the terminalalkenyl group with a hydrosilane compound having a crosslinkable silylgroup represented by the general formula (1) to thereby convert saidalkenyl group of said vinyl polymer to a crosslinkable silyl-containingsubstituent.
 10. The method according to claim 1, wherein the adhesivecurable composition further comprises a compound having both acrosslinkable silyl group and an organic group having at least one atomselected from the group consisting of nitrogen, oxygen and sulfur atoms,as an adhesion promoter.
 11. The method according to claim 1, whereinthe adhesive curable composition is a sealing composition.
 12. Themethod according to claim 11, wherein the sealing composition is packedas a one-component formulation so as to cure by crosslinking uponabsorption of moisture.
 13. The method according to claim 1, wherein theadhesive curable composition is a pressure sensitive adhesivecomposition.
 14. The method according to claim 13, wherein the pressuresensitive adhesive composition further comprises a tackifier resin. 15.The method according to claim 1, wherein the adhesive curablecomposition is a coating composition.
 16. The method according to claim1, wherein the adhesive curable composition is a powder coatingcomposition.
 17. The method according to claim 2, wherein the adhesivecurable composition comprises 0.01 to 20 parts by weight of an adhesionpromoter, relative to 100 parts by weight of said vinyl polymer.
 18. Themethod according to claim 2, wherein the vinyl polymer is a(meth)acrylic polymer.
 19. The method according to claim 2, wherein thevinyl polymer is produced by living radical polymerization.
 20. Themethod according to claim 2, wherein the vinyl polymer is produced byatom transfer radical polymerization.
 21. The method according to claim2, wherein said vinyl polymer has at least one crosslinkable silyl grouprepresented by the general formula (1) at a molecular chain terminus.22. The method according to claim 2, wherein the vinyl polymer having atleast one crosslinkable silyl group represented by the general formula(1) is produced by the steps of: (1) subjecting a vinyl monomer toradical polymerization using an organic halide or halogenated sulfonylcompound as the initiator and a transition metal complex as the catalystto produce a halogen-terminated vinyl polymer; (2) reacting saidhalogen-terminated vinyl polymer with an alkenyl-containing oxy anion tothereby effect substitution of the halogen to produce analkenyl-terminated vinyl polymer; and (3) reacting saidalkenyl-terminated vinyl polymer with a hydrosilane compound having acrosslinkable silyl group represented by the general formula (1). 23.The method according to claim 2, wherein the vinyl polymer having atleast one crosslinkable silyl group represented by the general formula(1) is produced by the steps of: (1) subjecting a vinyl monomer toliving radical polymerization to produce a vinyl polymer; and (2)consecutively reacting said vinyl polymer of step (1) with a compoundhaving at least two low-polymerizable alkenyl groups to produce analkenyl-terminated vinyl polymer and reacting the terminal alkenyl groupwith a hydrosilane compound having a crosslinkable silyl grouprepresented by the general formula (1) to thereby convert said alkenylgroup of said vinyl polymer to a crosslinkable silyl-containingsubstituent.
 24. The method according to claim 2, wherein the adhesivecurable composition further comprises a compound having both acrosslinkable silyl group and an organic group having at least one atomselected from the group consisting of nitrogen, oxygen and sulfur atoms,as an adhesion promoter.
 25. The method according to claim 2, whereinthe adhesive curable composition is a sealing composition.
 26. Themethod according to claim 25, wherein the sealing composition is packedas a one-component formulation so as to cure by crosslinking uponabsorption of moisture.
 27. The method according to claim 2, wherein theadhesive curable composition is a pressure sensitive adhesivecomposition.
 28. The method according to claim 27, wherein the pressuresensitive adhesive composition further comprises a tackifier resin. 29.The method according to claim 2, wherein the adhesive curablecomposition is a coating composition.
 30. The method according to claim2, wherein the adhesive curable composition is a powder coatingcomposition.